If you are trying to steel credentials from people with power and money passengers in first class are a good target.
Where else are you going to find a cluster of people like that that are using the wifi and are going to be there for hours. It’s about as optimal as I can think of.
Even better if you are targeting a spefic company. Just pick flights out of the headquarters for that company.
If you want to attack say Microsoft pick a flight from Seattle to DC. Pretty good odds of a Microsoft high up being on the flight and wanting to use the wifi for work.