According to flight aware, global air traffic is down 75%. So I'd bet mechanics aren't doing so hot either unless they were dedicated to cargo.
Programmers arent as easy to replace because they already understand the system. Training takes time, and if there's not enough documentation then you'll end up contacting the previous programmers for help (I've seen it happen) anyway.
Logically, that would extend to people whose job revolves around signing up restaurants to marketing portals. The restaurants that have an online business are already there. Those that don't have an online business are already closed.