The cine-goer attends this movie in order to "laugh" and "have fun". He/she ends up confused and disappointed. That's because he/she is missing the point: this is not a comedy, it's much more than that. Don't stay on surface, it's a political allegory in many ways. If the cine-goer could "get it" we'd probably be living in a different political order.
Spain and the crisis in the EU: the passengers (and viewers/cine-goers) in the second class are sleeping during the flight and cannot understand what is really happening. They have no right to the truth. The same applies to the viewer and critic, this movie is so clever that proves that the viewer/critic is also asleep since he/she can't get what's behind the "comedy".
It is only the A-Class passengers that are free of manipulation and have the right to know the truth. The crew could represent in a way, the "technocrats". However, they all have their own problems and ethics - it is criticized the way they came up to "A-Class".
Now, take a moment to think: why did we watch the first scene with Penelope Cruz? Just that the director lets his friends do a small guest part? It's a world where nobody is doing his/her job properly. Instead of that, everybody cares about his/her "personal world" which becomes that hilarious like when tweeting messages while bleeding. Further more, it's a world full of political corruption and economic scandals. When do they all come from? It's a world of a meaningless individualism. And, under pressure, it's all about sex. Hallelujah Sigmund Freud.