yeah when Locke said "let me go, i'll be alright" that freaked me out, like he knows something! woot!
I think it's more that he's made peace the island, somehow, and since he is a man of faith he believed he'd be ok.
"we're gonna have a locke problem"
I think that's why they showed him in the airport. he felt humiliated, inferior, embarrassed, emasculated when he was in the wheelchair. Then he crash-lands on the island, and his life is 100 times better. everyone else thinks its a disaster, and hates their situation and the island, but to him its salvation from a pathetic life. They definitely wanted the viewer to be reminded of the change in his quality of life.