I'm no plane specialist, and I'm guessing you aren't eirther. So let's be dignified and agree that at surface level, given the choice between bombing Germany and bombing Austria, Germany is a lot closer and simpler.
Logistics and distances have certainly also a lot to do with it. There were considered several reasons by Churchill and Roosevelt why some industrial areas in Austria weren't totally destroyed, but I'm posititive that Otto's intervention/plead was one of them. After all, in 2007 he gave his last interview at some Austrian newspaper, and he said so himself. Why would he lie?
@virumor
Just to be clear. I'm not blind of the atrrocities many "Austrians" have commited during WW2.
But let's also not forget that Austria was the first country that saw in the Nazis a danger, and the first country who officially prohibited the Nazi party and locked every party member into prison. This was commenced my the chancellor Engelbert Dollfu?. Of course he was then murdered by the Nazi party. Meanwhile, Britain and the Frenchies just sat around and did nothing.
Let's also not forget that the suffering back then was immense. 30% jobless rate, immensivle high interest rates to pay for bank loans, and lot's of starvation. Austria was back then ass poor. The public back then was actually naive enough to trust statesmen, so when Hitler made all his promises, the masses just believed him. Of course that he turned out to be a maniac and had plans for a war was never known - until it was too late. Now of course someone can argue that's not an excuse, and probbaly it isn't, but desperation often leads to ugly things.