Flying at 30 weeks?

Sia • First date: Oct 29 2011. He asked: July 29 2012. "I Do": June 29 2013. Mommy and Daddy to a son and 2 daughters. Maybe one more??
I have been planning to take a trip to visit my cousin (who is due 18 days after me!). I live in Maryland and she lives in Texas. My sister is going to fly with me so that I'm not alone, but the earliest we can both go is the end of May. That will put me at 30 weeks. I've already talked to my doctor and he's completely cool with me flying up until 35 weeks, but I wanted to get some other opinions. I'm not high risk and my first pregnancy progressed without any complications. Would you fly across the country at 30 weeks?