In the medical world, we're currently in the middle of interview season for positions beginning next July. This requires that I buy cross-country flights with little time flexibility, book many hotel stays, car rentals, and taxi rides. My colleagues have already spent several thousands of dollars in this process, but I've so far only spent a few hundred.
So this is how the process works: a hospital emails you an interview offer with two to eight interview dates. I've responded within five minutes at times, and had the interview date already be filled. So you have to be on top of your email game to get the interviews you want. After getting an interview date confirmed, finding flights that fit the tight schedule often will result in high ticket prices.