While all US passport holders are eligible, you’ll need one of the newer passports with a chip to use the e-passport gates. If you have a small symbol on the front of yours under the “United States of America” text that looks like the flag of Missouri then you’ve got one. If for any reason it doesn’t work, simply exit the gates and follow the guides to a regular immigration desk. It really is a breeze. If you’re in F or J you should have fast track which shortcuts you to dedicated lanes but honestly if the gate lines are short it’s just as fast either way (depends on terminal and time of day). AA flies into T3 from the States, BA into T5.