Tusayan Around operate a couple of agencie helicopters flying over the canyon with similar prices. Usually you have to book for the next day but last minute flights are available during the off season. You have to arrive half an hour before flight time for some instructions. Having said all there is the flight is a blast because I love helicopters and the landscape is amazing. There are different options choose from. The shortest flight, about 30min, cost about $129 for children and a little more for adults but not more than $150.