The following are aircraft that have either the wrong registration on ACARS or have some sort of 'non registration' id that has been tied up. I have NOT included the more obvious ones (like the FRD329 = N329K) nor have I included the 'temporary' ones (entry errors like United using fleet numbers - 2072 instead of N772UA, N428UAL instead of N428UA). Also not included are the ever so frequent problems noted with the "technologically advanced!!!" Boeing 777's being coded manually after the all too common occasions where the system gets reset (this is where the common errors like ..GVIIA, ..A6EMI, ..FGSPB, ...2072 (United fleet number), ....7AA (American fleet number), ....AKD (Saudia 'last 3') etc.) occur, and the silly bizjets JHBVLP (HBVLP) and NXAOVR (XAOVR). Also, several Delta 737-200s that are ex Western use a combo of DL and WA prefixes - this is in addition to the wrong registrations listed below. If anyone can help update this list please to not hesitate to E-mail me.
There are some additional 'regular' irregularities. N600DA is a generic id used by any Delta aircraft when that aircraft's unit is unavailable. 757s, 767s and MD11s have all been seen using it. Delta used to have another spare unit that they used for Tri-Star's (CGZZO) but that has not been seen since 1996. Other carriers use a generic unit/id, N1313Z, which has been used by (at least) British Airways and China Airlines. American Airlines use a flight id of AA0013 on a regular basis - this is NOT a real flight but some form of test/initialization id.
| ACARS | ACARS | ACTUAL | ACTUAL | |
| TYPE | REG | OPERATOR | REG | OPERATOR |
| Boeing 737 | D-AHLD | Hapag-Lloyd | HA-LER | Malev |
| Boeing 737 | D-AHLE | Hapag-Lloyd | HA-LEP | Malev |
| Boeing 737 | D-AHLR | Hapag-Lloyd | EI-CUA | Blue Panorama |
| Boeing 737 | D-AHLS | Hapag-Lloyd | D-AHLS | Blue Panorama |
| Airbus A310 | D-AIDM | Generic/'XX' | TU-TAZ | Air Afrique |
| BAe 146 | ECFFY | TNT Airways | OO-TAS | TNT Airways |
| Boeing 757 | EC-FYL | Iberia | N508NA | National Airlines |
| Gulfstream 5 | EFF005 | Private | EI-WGV | Private |
| Boeing 737 | EI-BPW | Delta Airlines(DL) | N367DL | Delta Airlines |
| Boeing 737 | EI-BPW | Western Airlines(WA) | N367DL | Delta Airlines |
| Boeing 737 | EI-BPY | Delta Airlines(DL) | N369DL | Delta Airlines |
| Boeing 737 | EI-BPY | Western Airlines(WA) | N369DL | Delta Airlines |
| Challenger | EJM48 | Bizjet | N48FU | Bizjet |
| Citation X | EJM630 | Bizjet | N630M | Bizjet |
| Gulfstream 4 | EJM997 | Bizjet | N997BC | Bizjet |
| Challenger | EXA63 | Bizjet | C-FBOM | Bizjet |
| BAe 125-800A | GJMAX | Bizjet | N41762 | Bizjet |
| MD-80 | N13809 | Continental | N809NY | Continental |
| MD-80 | N17843 | Continental | N938AS | Continental |
| MD-80 | N23842 | Continental | N936AS | Continental |
| Boeing 727 | N288SY | Sun Country | N288SC | Sun Country |
| Boeing 737 | N301P | US Airways | N300AU | US Airways |
| Boeing 737 | N310AU | US Airways | N266AU | US Airways |
| Boeing 737 | N311AU | US Airways | N267AU | US Airways |
| Boeing 737 | N312AU | US Airways | N268AU | US Airways |
| Boeing 737 | N313AU | US Airways | N269AU | US Airways |
| Boeing 737 | N313P | US Airways | N334US | US Airways |
| Boeing 737 | N314AU | US Airways | N270AU | US Airways |
| Boeing 737 | N314P | US Airways | N335US | US Airways |
| Boeing 737 | N315AU | US Airways | N271AU | US Airways |
| Boeing 737 | N315P | US Airways | N336US | US Airways |
| Boeing 737 | N316AU | US Airways | N272AU | US Airways |
| Boeing 737 | N316P | US Airways | N338US | US Airways |
| Boeing 737 | N317AU | US Airways | N273AU | US Airways |
| Boeing 737 | N317P | US Airways | N337US | US Airways |
| Boeing 737 | N318AU | US Airways | N274US | US Airways |
| Boeing 737 | N319AU | US Airways | N275AU | US Airways |
| Boeing 737 | N319P | US Airways | N339US | US Airways |
| Boeing 737 | N320AU | US Airways | N276AU | US Airways |
| Boeing 737 | N320P | US Airways | N340US | US Airways |
| Boeing 737 | N321AU | US Airways | N277AU | US Airways |
| Boeing 737 | N321P | US Airways | N341US | US Airways |
| Boeing 737 | N322AU | US Airways | N278AU | US Airways |
| Boeing 737 | N322P | US Airways | N342US | US Airways |
| Boeing 737 | N323AU | US Airways | N279AU | US Airways |
| Boeing 737 | N324AU | US Airways | N280AU | US Airways |
| Boeing 737 | N325AU | US Airways | N281AU | US Airways |
| Boeing 737 | N326AU | US Airways | N282AU | US Airways |
| Boeing 737 | N326P | US Airways | N346US | US Airways |
| Boeing 737 | N327AU | US Airways | N283AU | US Airways |
| Boeing 737 | N328AU | US Airways | N284AU | US Airways |
| Boeing 737 | N329AU | US Airways | N285AU | US Airways |
| Boeing 737 | N330AU | US Airways | N286AU | US Airways |
| Boeing 737 | N331AU | US Airways | N287AU | US Airways |
| Boeing 737 | N332AU | US Airways | N288AU | US Airways |
| Boeing 737 | N334P | US Airways | N349US | US Airways |
| Boeing 737 | N335P | US Airways | N350US | US Airways |
| Boeing 737 | N336P | US Airways | N351US | US Airways |
| Boeing 737 | N337P | US Airways | N352US | US Airways |
| Boeing 737 | N340P | US Airways | N353US | US Airways |
| Boeing 737 | N341P | US Airways | N354US | US Airways |
| Boeing 737 | N342P | US Airways | N355US | US Airways |
| Boeing 737 | N348P | US Airways | N356US | US Airways |
| Boeing 737 | N349P | US Airways | N573US | US Airways |
| Boeing 737 | N350AU | US Airways | N371US | US Airways |
| Boeing 737 | N350P | US Airways | N574US | US Airways |
| Boeing 737 | N352AU | US Airways | N373US | US Airways |
| Boeing 737 | N352P | US Airways | N575US | US Airways |
| Boeing 737 | N353AU | US Airways | N374US | US Airways |
| Boeing 737 | N353P | US Airways | N576US | US Airways |
| Boeing 737 | N354AU | US Airways | N375US | US Airways |
| Boeing 737 | N354P | US Airways | N577US | US Airways |
| Boeing 737 | N355AU | US Airways | N376US | US Airways |
| Boeing 737 | N355P | US Airways | N584US | US Airways |
| Boeing 737 | N356AU | US Airways | N383US | US Airways |
| Boeing 737 | N357AU | US Airways | N384US | US Airways |
| Boeing 737 | N358AU | US Airways | N385US | US Airways |
| Boeing 737 | N359AU | US Airways | N387US | US Airways |
| Boeing 737 | N361AU | US Airways | N389US | US Airways |
| Boeing 737 | N362AU | US Airways | N390US | US Airways |
| Boeing 737 | N363AU | US Airways | N391US | US Airways |
| Boeing 737 | N364AU | US Airways | N392US | US Airways |
| Boeing 737 | N365AU | US Airways | N393US | US Airways |
| Boeing 737 | N366AU | US Airways | N394US | US Airways |
| Boeing 737 | N367AU | US Airways | N395US | US Airways |
| Boeing 737 | N368AU | US Airways | N396US | US Airways |
| Boeing 737 | N369AU | US Airways | N397US | US Airways |
| Boeing 737 | N373AU | US Airways | N504AU | US Airways |
| Boeing 737 | N374AU | US Airways | N505AU | US Airways |
| Boeing 737 | N375AU | US Airways | N506AU | US Airways |
| Boeing 737 | N376AU | US Airways | N507AU | US Airways |
| Boeing 737 | N377AU | US Airways | N508AU | US Airways |
| Boeing 737 | N379AU | US Airways | N510AU | US Airways |
| Boeing 737 | N380AU | US Airways | N511AU | US Airways |
| Boeing 737 | N381AU | US Airways | N512AU | US Airways |
| Boeing 737 | N383AU | US Airways | N514AU | US Airways |
| Boeing 737 | N384AU | US Airways | N515AU | US Airways |
| Boeing 737 | N385AU | US Airways | N516AU | US Airways |
| Boeing 737 | N386AU | US Airways | N517AU | US Airways |
| Boeing 737 | N387AU | US Airways | N518AU | US Airways |
| Boeing 737 | N388AU | US Airways | N519AU | US Airways |
| Boeing 737 | N389AU | US Airways | N520AU | US Airways |
| Boeing 737 | N390AU | US Airways | N521AU | US Airways |
| Boeing 737 | N391AU | US Airways | N522AU | US Airways |
| Boeing 737 | N392AU | US Airways | N523AU | US Airways |
| Boeing 737 | N393AU | US Airways | N524AU | US Airways |
| Boeing 737 | N394AU | US Airways | N525AU | US Airways |
| Boeing 737 | N395AU | US Airways | N526AU | US Airways |
| Boeing 737 | N396AU | US Airways | N527AU | US Airways |
| Boeing 747 | N620UP | UPS | N520UP | UPS |
| Boeing 747 | N621UP | UPS | N521UP | UPS |
| Boeing 747 | N622UP | UPS | N522UP | UPS |
| Boeing 747 | N623UP | UPS | N523UP | UPS |
| Boeing 747 | N624UP | UPS | N524UP | UPS |
| Boeing 747 | N625UP | UPS | N525UP | UPS |
| BAe 125-800XP | N699EC | Bizjet | CSDNH | Bizjet |
| Boeing 737 | N761N | Piedmont | N223US | US Airways |
| Boeing 737 | N762N | Piedmont | N224US | US Airways |
| Boeing 737 | N763N | Piedmont | N225US | US Airways |
| Boeing 737 | N768N | Piedmont | N226US | US Airways |
| Boeing 737 | N769N | Piedmont | N227AU | US Airways |
| Boeing 737 | N772N | Piedmont | N228US | US Airways |
| Boeing 737 | N773N | Piedmont | N229US | US Airways |
| Boeing 737 | N775N | Piedmont | N231US | US Airways |
| Boeing 737 | N778N | Piedmont | N232US | US Airways |
| Boeing 737 | N779N | Piedmont | N233US | US Airways |
| Boeing 737 | N780N | Piedmont | N234US | US Airways |
| Boeing 737 | N781N | Piedmont | N235US | US Airways |
| Boeing 737 | N782N | Piedmont | N236US | US Airways |
| Boeing 737 | N783N | Piedmont | N237US | US Airways |
| Boeing 737 | N784N | Piedmont | N239US | US Airways |
| Boeing 737 | N785N | Piedmont | N240AU | US Airways |
| Boeing 737 | N786N | Piedmont | N241US | US Airways |
| Boeing 737 | N787N | Piedmont | N242US | US Airways |
| Boeing 737 | N788N | Piedmont | N243US | US Airways |
| Boeing 737 | N791N | Piedmont | N244US | US Airways |
| Boeing 737 | N792N | Piedmont | N246US | US Airways |
| Boeing 737 | N793N | Piedmont | N247US | US Airways |
| Boeing 737 | N794N | Piedmont | N248US | US Airways |
| Boeing 737 | N795N | Piedmont | N249US | US Airways |
| Boeing 737 | N796N | Piedmont | N251AU | US Airways |
| Boeing 737 | N797N | Piedmont | N252AU | US Airways |
| Boeing 737 | N798N | Piedmont | N245US | US Airways |
| Boeing 737 | N799N | Piedmont | N253AU | US Airways |
| Boeing 737 | N802N | Piedmont | N254AU | US Airways |
| Boeing 737 | N803N | Piedmont | N255AU | US Airways |
| Boeing 737 | N804N | Piedmont | N256AU | US Airways |
| Boeing 737 | N805N | Piedmont | N257AU | US Airways |
| Boeing 737 | N806N | Piedmont | N259AU | US Airways |
| Boeing 737 | N807N | Piedmont | N260AU | US Airways |
| Boeing 737 | N809N | Piedmont | N261AU | US Airways |
| Boeing 737 | N810N | Piedmont | N262AU | US Airways |
| Boeing 737 | N811N | Piedmont | N263AU | US Airways |
| Boeing 737 | N813N | Piedmont | N264AU | US Airways |
| Boeing 737 | N814N | Piedmont | N265AU | US Airways |
| Boeing 727 | N921UP | UPS | OY-UPB | UPS(Starair) |
| Boeing 727 | N923UP | UPS | OY-UPM | UPS(Starair) |
| Boeing 727 | N926UP | UPS | OY-UPA | UPS(Starair) |
| Boeing 727 | N927UP | UPS | OY-UPS | UPS(Starair) |
| Boeing 727 | N943UP | UPS | OY-UPJ | UPS(Starair) |
| Boeing 727 | N944UP | UPS | OY-UPD | UPS(Starair) |
| Boeing 727 | N945UP | UPS | OY-UPT | UPS(Starair) |
| Grumman C-37 | S70400 | USAF | 70400 | USAF |
| Grumman C-37 | S70401 | USAF | 70401 | USAF |
| Falcon 2000 | SWQ228 | Bizjet | N228EJ | Bizjet |
| Citation X | SWQ938 | Bizjet | N938EJ | Bizjet |
| Citation X | SWQ991 | Bizjet | N991EJ | Bizjet |
| Citation X | SWQ998 | Bizjet | N998EJ | Bizjet |
| Airbus A320 | TC-OND | Mexicana | SU-LBA | Lotus Air |
| Citation V | UASC1 | Bizjet | N35TF | Bizjet |
| Canadair RJ | XER51 | Bizjet | N5100X | Bizjet |