Ah... I have an answer! I live in an area of Washington State called the Tri-Cities. Our main airport, Tri-cities intnl. airport (KPSC) is served by 5 major airlines (2 if you don't consider Sky West, Horizon, or United Express as major airlines). The airlines that serve here are those listed above, and also Delta and FedEx. Well, we have a Delta flight depart at about 8pm every night. I, being an avid plane spotter, usually memorize the N numbers and check for pics of the planes here. All the Delta flights out of here are 737-200's. Every day, the N number on the aircraft is different, and the one that flies over my house every day is, on certain days, in the old colours, and on others, new colours, so obviously different aircraft.