BERLIN/FRANKFURT (dpa-AFX) - Several German airlines are testing procedures to avoid climate-damaging contrails in the sky. Lufthansa, Condor, Tuifly and the freight companies DHL and EAT are taking part in the "100 Flights Program", as the industry association BDL announced in Berlin on Wednesday.

In cooperation with German air traffic control and Eurocontrol, flight routes could be optimized, it said. Aircraft then avoid flying through particularly humid and cold air masses. Otherwise, the warm exhaust gases from the engines condense here and form small cirrus clouds, which reflect the heat radiation from the earth and thus increase the greenhouse effect. The areas can be localized using satellites.

It remains to be seen whether flying around the sometimes very large air masses can actually have a positive effect on the climate. To this end, the climate impact of the avoided contrails must be compared with the additional CO2 emissions.

According to the BDL, final results are still pending and will be evaluated with scientific institutions. It is already clear that more climate-friendly flying requires automated flight planning processes. "It is important to us that the 100-flights program is not a lone lighthouse project, but part of our extensive activities to further develop climate-neutral aviation," emphasized BDL Managing Director Matthias von Randow.