Most of the pro teams charter a plane from someone. The Vikings, Twins, and Packers charter Northwest. I believe the Wolves also charter with Northwest as well. The NFL's Eagles, Panthers, and Steelers have US Air planes painted up in the team scheme, but the rest of the time the plane is just another in the US Air rotation. You could book a trip to wherever and ride on the team's plane. The only teams that i can think of that have their own plane is the Red Wings and Tigers, both of which are owned by Mike Illich, the Caesars pizza guy. That being said, i have no idea what they do with that plane when neither team is using it.
You guys gotta remember that an airbus costs between $60-90 million. Pretty big cost to have it on standby for 30ish trips for a MLB team, 10 for an NFL team, 42 for a NHL, and 40 or so for an NBA team. Obviously, that doesnt count playoffs, but you get the idea.
Also, i attached the DC9 for the Red Wings and Tigers.