I buy chocolates, cookies, etc. from the airport shops, after going through security, and give it to the flight attendants.
To avoid suspicion, I keep it all in the original packaging, leave it in the store's bag, and show the receipt.
Sometimes, I catch crew members having a nosh in the galley. 😁
They have an irksome job, dealing with too many loutish passengers. I'm happy to be able to brighten their day when I'm on a flight.