It looks like all your cards are of the cashback type. The quickest, most efficient path to free flights is large credit card sign-up bonuses. Think airline cards and cards where you can transfer points to airlines (Chase Ultimate Rewards cards and Amex Membership Rewards cards.) From Las Vegas, maybe consider getting two Southwest 50K Cards and obtain Companion Pass for 2016 and 2017. Do some research on that to ensure your points all post in the right year.