I know to most people this question will seem silly but I have only flown once in my life and it was a straight flight to the next state. I am pricing flights to Cancun and have found some that fly from where I am to Houston and there is only as 55 minute layover then flight to Cancun. I am wondering if that is enough time normally (I know it varies considerably) to switch planes. It is with the same airline. These are the only flights that will get me there at the time I prefer. I am assuming there is no customs to go through leaving the US? Is it just when returning? I know this may seem like something I should know but when you don't travel there are many simple questions that you just don't know. Thanks!