Airplane Position Trails and Satellite / Iridium Flares are always annoying in timelapses as they distract from the natural beauty of the Night Sky.
Especially worth removing them is with Meteor Showers as the annual Perseids.
Watch the difference between a rotoscoped Perseid / Milky Way shot and a non-rotoscoped.
Doing this frame-by-frame makes it easier to differentiate between a Perseid streak or Satellite flare. So in the cleaned version you see Perseids only.
You can learn this processing technique at the "2015 Astromaster IV" course, taking place October 3rd to 8th on the beautiful Island of La Palma, Canary Islands, Spain.
All the best,