The recommended layover time for domestic flights is normally one hour. However, as previously stated, you may require longer if your flights are booked with two different airlines, if you are traveling to a very busy airport or if you require special assistance.
What is the minimum connection time at O Hare?
How long do I need for a connection at ORD? If the flights are with the same airline, gates are typically a very short walk and you can make connections that are 30 minutes or a little less. For domestic flights on different airlines where you have to switch terminals, plan for a minimum one hour connection.
Do you have to go through TSA again for a layover?
For connecting domestic flights, you almost never have to exit and reenter security, though there are some exceptions at airports where the terminals aren't all connected. For domestic-to-international connection, it's still pretty rare that you have to exit and reenter security, even if you're changing terminals.