What, a trade deal? If the UK wants one I'm pretty sure they'll get one under a Trump Administration. I can just about guarantee it'll go through
faster and easier than CETA. There's not really any reason not to... and TTIP's starting to come apart at the seams anyway.
One of the fun things the Maastricht Treaty ended up doing is killing off a lot of the automotive and aerospace components trade between the US and the UK. Lucas was at one point quietly selling a huge proportion of their production to the US - many Mustangs have Lucas-made fuel injectors; they had Lucas made fog lights and other accessories as options. GM also bought Lucas parts. Most of that trade went poof in the wake of Maastricht for various related reasons; German industry made out like a bandit, capturing no small part of the lost UK business for some strange reason... I wonder what that would be.
Many people would like to see that trade resume in both countries; the UK would probably appreciate the resurrection of that manufacturing sector and US companies purchasing such goods would love to be able to (if nothing else) have another source to play off against others and get prices down while still getting quality parts.
To choose another example, it means the US would have a huge new exclusive customer for all this natural gas we can't seem to get rid of because the current administration was dragging its feet on gas export terminals. The UK would get cheaper prices on fuel
(they currently import 55% of their natural gas with the rest coming from UK production sources) because we gotta dump this stuff and we'd make a lot of money anyway. It could also remove them from dependence on European (read: Russian!) gas.