A new study from NASA has shown that the jet engines using biofuels have fewer particle emissions in their exhaust trails.
"As a result, the observed particle reductions we've measured during ACCESS should directly translate into reduced ice crystal concentrations in contrails, which in turn should help minimize their impact on Earth's environment,"http://www.cnbc.com/2017/03/17/biofuels-cut-jet-engine-pollution-nasa-study-shows.html
I believe that aviation over the Arctic ocean contributes to the creation of polar stratospheric clouds. These contribute to the warming over the Arctic, according to a research paper previously reported on the forum.
Scientists recently discovered that polar stratospheric clouds, long known to play an important role in Antarctic ozone destruction, are occurring with increasing frequency in the Arctic. The PSCs have been frequently seen in northern parts of Scandinavia during this winter, according to various reports.http://earthsky.org/earth/wow-polar-stratospheric-clouds