Cockatiels flying away?

I posted a long post about what happened to my two cockatiels, but they were basically neglected for a long period of time when I went to college. As a result, they are no longer trained very well (Leo used to fly to my finger if I held my hand up) and have trust issues. Luckily, I have them back, but I understand that I have a lot of rehabilitation work with them to do.

They both have issues flying away, and I mean panicked flying. My dad would take them out, and then they would be out for an hour, and put back again. They then would not be taken out for weeks at a time. So now they associate fingers with being put back and neglected. My boyfriend and I are now taking them out regularly, but every time we try to handle them, they fly away. Getting them into the cage for bedtime is a nightmare.
Note: Sometimes Beaker will step up on my hand and let me pet him. Leo still hisses at my fingers and bites a little bit. Not too hard, but he is definitely biting.

Things we are doing:
-Not raising our voices. We speak sternly and say "step up," but this is usually not obeyed. We are being as compassionate as possible.
-If one stays on us, they get a nibble of a treat.
-If they go into the cage, they get a treat. But sometimes they hiss at the treats, but eventually if I coo at them and speak softly, they will nibble.
- Like I said, taking them out frequently.
- The cage is not the only place they go. We tried taking them into the dining room to nibble at their own bird plate with us tonight for the first time. They watched us eat from a distance.

Things we are considering:
- Wing clipping. We'd have to take them to the vet to do it because they are so spastic now.

I'm asking for other suggestions?

Welcome!
Thank you for wanting to make your birds' lives better.
Lots of cockatiel lovers and owners here.
Pending their replies... My advice... take any issue or topic which interests you, and use the Search Tab to read, read, read about it. I do that a lot. The people here are an amazing source of information, advice, and support. I'm glad you found this place!

It sounds like you are being extremely patient and doing the right things. It sounds like you're gaining trust very fast. But there are definitely people with teil experience that might be able to help more than I. I do agree that if you decide to clip to have the vet do it due to the fearful state they are already recovering from.

CherylCali