We are flying to London next month and the flight schedule is from Birmingham to Detroit and then four hours later to London. I know the suggested time to be at the airport is three hours for international flight but in our case this would just be the Detroit/London portion and not Birmingham/Detroit leg, correct?
That is correct. Your first flight is national...use that recommended time.
Thanks, Maria!
Domestically between Birmingham and Detroit, I would arrive 2 hours in advance. I travel domestically for business weekly. There is no need to arrive 3 hours early at the Birmingham airport for your flight to Detroit. You are not going to have any extra security lines at Birmingham because your final destination is London. Check in online 24 hours beforehand. If you are flying Delta via Detroit (obviously I'm guessing), at the bag dropoff if you are checking luggage, you will be asked for your passport.
Check with your airline. Even though the first leg is domestic if this is all one ticket it is considered an international flight. It is likely you’ll have a passport check at Birmingham.