Try JETLEV

The JetLev-Flyer Water Jet Pack is a water powered jetpack that provides a close-to-flying experience.
The product can only be used on water and allows the user to fly at up to 8.5m, controlling height, direction and speed by handheld controls. It's powered by water sent up through a tube to a jetpack attached to the user's back. Two pressure guns fire water into the lake or river, generating enough power to push the user into the air.
Source: ehow.com