If he needs to fly to DC and back on an F-16, then maybe people can start a go-fund-me page to offset the cost of the flight. Those fighters are pretty doggone fast!
.
I don't believe there are any versions of the F-16 with two seats, I don't believe Daines is checked for solo in the bird and after meeting him a couple of times I think he's too tall for ejection seats anyway.
Most charter and commercial aircraft can get as close to supersonic as is legal over CONUS airspace, but it would be a real kick in the butt to have the Senator fly back MIL and go high speed pass over the Capitol on his way to vote.