First of all I'm loving Xenonauts! It's exactly what I've been after for a number of years. I've been playing for a few months now on the experimental builds and it's been fantastic.
I don't know if it's already been reported, but yesterday I was playing release 1.0 on the stable branch and hit a crash. I'd finished a mission and was flying back. I opened up the save screen to save the game, but then changed my mind and wanted to keep playing so hit Cancel. That crashed it.
I haven't tried to repro and unfortunately don't have a save that could reproduce it, but wanted to just give you folks a heads up in case it hadn't been reported before.