Generally speaking, most airlines advise that you arrive at the airport at least 2 hours prior to a domestic flight, and at least 3 hours prior to an international flight.
Is 40 minutes enough time for a layover in Philadelphia? That depends if you are domestic and just switching planes and using the same carrier, and it is in the same terminal yes. you wont have any time to do anything but go straight to your gate.
You are allowed to bring a quart-sized bag of liquids, aerosols, gels, creams and pastes through the checkpoint.These are limited to 3.4 ounces (100 milliliters) or less per item. This is also known as the 3-1-1 liquids rule.
How long does it take to get approved? Most applicants receive approval notification in 3-5 days, though some applications can take up to 60 days. Considering this, applicants are encouraged to renew at least 60 days prior to expiry. TSA will notify members with eligibility results.
TSA PreCheck® provides expedited security screening benefits for flights departing from U.S. Airports. Global Entry provides expedited U.S. customs screening for international air travelers when entering the United States. Global Entry members also receive TSA PreCheck® benefits as part of their membership.