Scientists are planning to shape nuclear-powered planes that may allow passengers change flights mid-air and jets refuel in the sky. The next generation of air travel would allow passengers to be delivered to the behemoths via smaller planes, along with their luggage, the Mirror reported.

Engineers are also working on “flying petrol stations” that could enable non-stop flights, the Mirror reported. Refueling in the skies would cut the amount of fuel planes need for take-off, when they are heaviest, making them better for the environment.

The concept has been tested with the help of professional pilots using simulators but, four years in, researchers have yet to trial anything in flight.