We have a connecting international flight to London in September through Atlanta. After booking I notice that the layover time was 1hour, 38 minutes. I wasn't too worried until I decide to research a little more and found that although the flight is rarely cancelled, it has a poor on-time rating, running 35 minutes late. Called Delta to try for the earlier flight, $150 each change fee. There are 4 of us, for a total of $600. Is this something I should not worry about? There are two more flights out that day to London, but we upgraded our seats and it could be possible not to get the upgrades on the next flight. Someone told me to try going to our local airport and see if the ticketing agent could help, but that is an 1 1/2 (rounds trip) from my home. Help from experienced travelers is greatly appreciated!