[xone]

but what were those US planes looking for

Not looking for, surveillance on a target.

[Bigg Red]

Okay, thanks.

[generally]

1. What planes?
2. Why wouldn’t they use a helicopter?

Another guess:

If you use keep planes in the air taking photographs, then when an event happens, you can track every single vehicle on the road to see where it came from and where it went.

So maybe they were expecting something to happen in PA but didn’t know quite who or where.