I'm just curious as to why airlines change flight numbers. I know airlines change the flight number after a major incident, but that is all I know. My example involves the DL mainline flights here in SYR. When Delta started mainline back up here in Syracuse, the flight was an arrival at night around 10:30 as DAL1225 while the departure in the morning was DAL1226. When DL added a second mainline flight April 1, the night time arrival turned into DAL851 while the morning departure remained DAL1226. The new late afternoon arrival was DAL990 while the departure was the same number. Well, DL just changed the flight numbers again. Now, the late afternoon arrival is DAL2281 and the departure is DAL1249. The over night arrival has now been changed to DAL853 and the morning departure is DAL855. All flights remain MD88's as well. Does anyone know why they change the flight numbers so much? I'm just curious.