Yeah the antenna thing is a real heart-stopper. Get some basic childproof window locks, the sliding kind. They're cheap and buy you time to figure out the trust thing.
Parrots are incredibly smart and can often outsmart simple locks. Childproof window locks might slow them down, but a determined bird can still figure them out. You might need to look into locks made specifically for pets or even add secondary latches. Combining better security with trust training is probably the best way to go. It's a balancing act between keeping them safe and letting them have some freedom.