If you are in the wedding party, such as a bridesmaid, groomsmen, or other attendant, please arrive no later than Wednesday the 5th. All other guests please arrive no later than Thursday the 6th. Katie and Matt will arrive Tuesday the 4th.
You can fly whatever airline you would like. I personally use Southwest points to book our flights to Cancun. Here is the link to apply for a Southwest card and start earning points. https://www.referyourchasecard.com/226f/A3WHPV1WJN
The recommended airport is Cancun, however there are other options. They recently built a new airport in Tulum that you can fly into instead. They are both about the same distance from the resort, which is next door to Puerto Aventuras. The distance from the airports to the resort, is about an 1 hour.