In the 90s Sega was in direct competition with Nintendo. Not just with their home consoles, but with their portable systems as well. We all know who the winner was in that battle, but Sega proved that it was willing to try new things and one-up Nintendo at just about every corner. The Sega Mega Jet was one of those things.

So, what was the Sega Mega Jet? It essentially was the predecessor to the Sega Nomad, a portable console that could play Genesis games. Only the Mega Jet lacked a screen. Initially, the console was rented for use on Japanese Airlines

The device lacked its own screen but could play Mega Drive cartridges when connected to a small armrest monitor used on JAL flights. The unit featured a directional pad on the left side and six buttons on the right, similar to the layout of a game controller. There was a second joypad port on the bottom of the Mega Jet for multiplayer games.

A consumer version of Mega Jet was released by Sega of Japan on March 10, 1994 at the cost US $123. It was essentially the same as the unit that was used on JAL flights, meaning that it still lacked a screen and couldn’t be powered without an AC adapter. Other than the addition of a mono DIN plug cord and the necessary AC adapter, no other additions or improvements were made.

–Sega Wikia