A member of my family with the MBA does a fair bit of traveling. He always has to remove his MacBook Air when he goes through security. They never let him keep it in his bag.
The people at the security checkpoints are some of the most disgruntled people on the planet. I think they enjoy sharing their misery by making folks remove their laptops from their bags.
Wonder what it is about the iPad that allows it to stay in a bag while being x-rayred? About the only difference between an iPad and a MBA is the keyboard. That and maybe a pound more in weight.
It could be worse. In the beginning days of laptops, we had to "fire" them up to show that they were actually computers.
As to the TSA people, I think it's about power. About the only other place they can get this type of power is becoming prison guard.
I remember the days of "firing them up". When the Titanium PowerBook G4 was brand new and I was travelling, the security guy did not believe that it was real. He pulled me off to the side, got his supervisor, and made me turn it on to prove it wasn't a weapon or something. This in the days when 3 inch thick PCs were not uncommon.
Fear the power of my 500 MHz G4!
I just flew with my MBA without taking it out of the case. If the computer has its own compartment, and you have NOTHING else in the case, you can leave it in the case. You have to place the case by itself in a bin, nothing underneath and nothing on top. Any sleeve or case will do, as long as you follow these rules. They were posted at the airports I went through (SJU, MCO, MSP)