I don't know how the priorities work between and and or. This line
this or NOT(alive pl1) and NOT(alive pl2)
might need more brackets.
thislist commands will work correctly only if the units to which you are referring would be captured by the activation box. I suspect grouping the trigger to the player is going to be unhelpful in this case.
When you've got multiple logic things going on like this, it's a good idea to get a way from the computer for a bit. Write down on a piece paper, graphically or in words, what you are trying to do. You must have it crystal clear in your head before trying to write condition fields for triggers, otherwise it won't work and you end up going round in circles.
hopefully this will mean if the pilots land and the civ joins them, as they are walkin back to the chopper if i kill both pilots the civ will join me automatically. Is this correct?
NEVER write anything like this in a post. Try it first. Experiment, experiment, experiment. The forum is where you turn when you can think what else to do.