One of the advantages of being a millionaire industrialist genius inventor with a flying suit of cybernetic armor is that you don't have to wait for your plane to be on the ground in order to perform repairs.
Of course, one might wonder why you would need a plane in the first place, but they probably aren't millionaire industrialist genius inventors with flying suits of cybernetic armor, so screw them.
The mid-1980's were characterized for Iron Man by an extreme slowdown in his Avenging schedule. He recovered from a major relapse into alcoholism and lost much of his fortune. At one point he even needed to pick up a bit of employment on the side as a construction worker.