If you are flying into the U.S. and connecting to a domestic flight, then a 50 minute layover will be insufficient. In that time span, you would have to deplane, go through immigration, collect your bags, pass through customs, drop your bags, reclear security and then make it to your gate for your next flight.
Is 45 min layover enough in DFW?
If you're on American and connecting to an American flight at DFW, it could be iffy, depending on whether you have to change terminals. If you're changing airlines at DFW, the odds are you have to change terminals and it's not enough.
Is 45 minutes enough time for a layover in DFW?
Travel time between terminals can take as long as 30 to 45 minutes; so it would be in your best interest to allow at least 1 and 1/2 hours to 2 hours layover time. If your flight into DFW should be delayed, 40 minutes almost guarantees you would miss your connecting flight.