Continuity mistake: When Arthur is shot in the head, at first there's no bullet hole in his head, but in the next shot there is.
Continuity mistake: In the scene on the airplane when they are setting up to go under, Yusuf takes a sip from a wine glass and goes to set it down. Then in the shot immediately following he no longer has a wine glass in his hand. Instead he is buckling his seat belt. (01:03:50)
Revealing mistake: When the chase in Mombasa has just begun, the camera is moving in front of Cobb at one point. Notice how the people behind the camera are moving into Cobb's paths, despite the fact that they weren't there a second ago?
Continuity mistake: As Cobb is explaining to Ariadne the importance of imagining new places to create dreams, the positions of his head, arms and hands change between shots.
Chosen answer: He bought out the actual airline company. If he'd bought out all the tickets for that specific journey he'd have said "I bought out the flight" or similar. It's a deliberately over the top moment of exuberance to highlight exactly how rich Satio is. I'm afraid that it is your friend who is correct, sorry.
Manky