This one was on my radar so grabbed it for less than a dollar
"In Air Mail, you play as Scoop, a plucky young lad who sneaks into a small aircraft hanger, and ends up becoming the greatest pilot of his age. During the course of the game, you'll guide Scoop on perilous adventures through a gorgeously realised steampunk-lite world.
As you might imagine, some missions involve picking up and dropping off packages, but there's a wealth of other content to explore, too. You'll fly through rings to prove your aerobatic skills to the other pilots, collect crystals, drop pesticides, and run dangerous sorties through tight canyons.
Express Delivery mode lets you fly different challenges, trying to set high scores, while Explore mode lets you discover the world you're flying in, seeking out hidden treasures as you do."
Some good reviews
"…Air Mail is packed with moments that will put a smile on your face."
— Slide To Play, 4/4
"This is one of my favorite high-flying games on iOS."
— TouchGen, 4.5/5
"…we're proud to call Air Mail one of the tablet's most visually-arresting titles."
— Modojo, 4/5 Stars
"I can not stress how amazing this flying game is."
— App-Score, 10/10
"…anyone with a Retina iOS device should have a copy of Air Mail, one of the best games I’ve played so far this year."
— AppTudes, 4.5/5
"Air Mail is a top notch iOS experience that really delivers on all levels making it a must buy."
— AppleNApps, 4.5/5
Doesn't work on 3GS