The Antares DLR-H2 research aircraft is the first crewed plane worldwide that is entirely powered by fuel cells. Because of its unique powertrain, it can take off, fly, and land without emitting any CO2. The fuel it uses is hydrogen that is converted into electric energy in a direct electro-chemical reaction with atmospheric oxygen. The process does not involve combustion. The end product of this particulate-free reaction is only water. The fuel-cell system and the hydrogen tank are installed in two external pods mounted below the wings, which have been reinforced for this purpose. In the spring of 2009, Antares DLR-H2 demonstrated its flight capability. Now it uses a new, more efficient generation of fuel cells. The additional option of hybrid operation using storage batteries installed in the wings maximizes the aircraft's peak power.