Football teams and some mens basketball programs fly on charters.

Most teams, including many mens basketball teams, fly commercial. The Big 12 is not a bus league like much of the ACC and SEC, and a number of those programs are in towns that don't have a lot of commercial service. Texas and TCU are relatively easy to reach because they are in relatively big cities with lots of flights. There are not a lot of options to reach and leave places like Lubbock, and for places like Morgantown and Ames and Stillwater, you've got to bus for a fair distance to get to the commercial airport.

If you add to that a change in time zones, it becomes problematic. During WVU's first year in the Big 12, that meant kids getting home at 4 am, kids away from class more, etc. There are or were rules that said kids had to return home in between road games so you might play in Lubbock on a Saturday, fly home that night or Sunday, then have to fly out on Monday for a Tuesday game in Norman rather than just going from Lubbock to Norman directly. To the Big 12's credit, they have done some things with the schedule to make it better for WVU's athletes.

I traveled a bit with Tech's basketball team back in the 1980s. It's not just as simple as whether you can fly from point A to point B in 2 or 4 hours. You can love the Charlotte airport but you're going to have limited options to get to and from Roanoke.