"Flying is a manual skill" Not sure that statement hold for those that went 200 hours straight to an Airbus.
I think in the current climate property development isn't going to be that viable noting that house prices are predicted to fall. That said there may be a lot of repossessed houses in the next 12 months going cheap, but unless you have the cash to buy and can wait for the market to recover before selling I can't see it is something that will yield an immediate income.