If you have over $10k you are supposed to declare it at the airport.
Make sure you sign up to a frequent flyer programme - a trip to vegas is worth a decent amount of air miles!
You could either join the American Airlines one or British Airways (or any other memer of 'One World')
http://www.aa.com/apps/AAdvantage/AAdvantageHome.jhtml?anchorLocation=DirectURL&title=aadvantage