Continuity mistake: Just before the shifting gravity, Arthur walks out of the room and begins walking down the hallway. As we see him from behind, the elevator door opens and a projection is revealed. But, when the elevator doors are opening, Arthur slows down and just before we see him from the front view shot, his bead begins to tilt down. Then in the front view shot, he slows and tilts his head down again to avoid the projections contact.
Continuity mistake: In the dream-café Ariadne raises her arm to scratch her head, but in the next angle the hand is down.
Continuity mistake: In the café, Ariadne lifts her cup to take a drink and in the very next shot she is putting the cup back down.
Continuity mistake: In the scene where Fischer is talking to Browning by his father's bed, in one shot, Fischer changes from looking straight at Browning to looking down at the ground.
Continuity mistake: When Cobb tells Ariadne to draw a maze, she turns her head to the left. A frame later the head is up and she is turning it again.
Continuity mistake: When Cobb hands Fischer the gun in the bathroom, the gun switches hands for one shot.
Continuity mistake: When Adriadne and Cobb sit down, a newspaper stand explodes, but in the next shot it's still standing.
Continuity mistake: As they are sitting around, planning the next job, Cobb is wearing a blue shirt, of which he rolls up the right sleeve repeatedly.
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: 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