We know tons about AGI already, why do people presume we need to learn more? (It's totally obvious how to make safe airplanes before you have a Wright flyer. Use lots of cushions, use two engines, make everything redundant actually, make everything of incredibly high quality material, et cetera. I think your analogy is way too leaky.)
I think you cannot figure out airplane safety before you build airplanes. For example, you'd have to be almost superhumanly smart to predict and beat flutter without experimenting. Or spin, as Kaj_Sotala pointed out. Or spatial disorientation. Even without going into details, can you complete the list of problems by yourself?
One of the reasons that I am skeptical of contributing money to the SIAI is that I simply don't know what they would do with more money. The SIAI currently seems to be viable. Another reason is that I believe that an empirical approach is required, that we need to learn more about the nature of intelligence before we can even attempt to solve something like friendly AI.
I bring this up because I just came across an old post (2007) on the SIAI blog:
Some questions:
I also have some questions regarding the hiring of experts. Is there a way to figure out what exactly the current crew is working on in terms of friendly AI research? Peter de Blanc seems to be the only person who has done some actual work related to artificial intelligence.
I am aware that preparatory groundwork has to be done and capital has to be raised. But why is there no timeline? Why is there no progress report? What is missing for the SIAI to actually start working on friendly AI? The Singularity Institute is 10 years old, what is planned for the decade ahead?