Birdman Warps= There are several warps hidden througout this game. Here's how to find a few of them: To warp to the Birdman stage, fly under the bridge on the first level. Grab the star and you'll be free as a bird.
You can also become the birdman by flying to New York (on Little States Island) with the rocketbelt and touching the golden star in Central Park.
In Everfrost island use the rocket belt in the first test look to your side and you will see waterfalls. Go to the right most waterfall and go in the cavern. Keep going until you see another waterfall go down there and you will see the star that warps you to the birdman stage for everfrost.

Cannonball Tips= The following settings will land you in the bullseye on the first try, but you'll need to adjust the shots a bit for optimal results. Apparently you can't get a perfect score if you don't fiddle with the settings first.

Get a 100 on Jumble Hopper Mission 3= The building to the right of the one that you start out on has an entrance at the base. If you go through it you will warp to New York which is very close to your goal in Washington D.C. If you have difficulty try to angle off the other building to get close to or into the hall.

Mt. Wario= Get to class B with the Gyro Copter and fly to Mt. Rushmore. Shoot Mario in the nose and he'll morph into Wario.

Night on Beginner Course= In the beginner course, you'll find a cave in front of a chapel on top of the hill. There should be water coming out of cave, and a sewer grate deep inside. Fly up to the sewer grate and the game will pause a little and make a weird sound. The cave should be darker, when you leave the cave you'll see that it is night time!

Unlimited Fuel - Japanese= Stay in the air longer with this code. For unlimited fuel, pause the game and press Up, Down, Left, Right. Unpause and you'll have all the fuel you need.

Warp to San Francisco= With this trick you can warp from New York to San Francisco. Start on Little States Island and select either the Rocketbelt or the Gyrocopter. Travel west from Central Park to the building with an open door. Walk inside past the N64 logo, and look for another door to exit. You'll find yourself in San Francisco.

Warp to Washington= In Florida, fly to the small warehouse. You should see a small opening. Enter it and check out the details. When you leave you'll find yourself in Washington! To return to Florida, simply re-enter the warehouse.