Is Wilson coming or going?

Throughout the movie we are given shots of Wilson sitting in an airplane intercut in between important areas of dialogue were the film's experimental editing style are feature most.

But I ask you, is Wilson coming or going?

Most people seem to assume that this film is based on his memories, as we see into the future during different scenes. Or that the dialogue sequences that take place in different locations are results from the memories playing tricks on their owners, and that Wilson knows this dialogue took place, he just doesn't remember where.

But I have an idea that maybe this entire movie takes place in Wilson's head before he even lands in America. Could all the images we see simply be what Wilson believes will happen when he gets there. Who hasn't sat down before an important event and imagine what will take place? And it never happens in the right order. You may be thinking of one aspect which will cause your mind to jump to something else for a moment. Could this whole movie be simply what Wilson hopes happened to his daughter?

So what do you think? Coming or going?