EasyJet wants European lawmakers to put a cap on the age of commercial aircraft that can be operated. If EasyJet gets their way all planes over 22 years old would have to be retired and replaced with younger aircraft. While Airbus, Boeing, Embraer and Bombardier would surely approve of such a plan, it's really rather disingenuous of EasyJet to claim this will help the environment.
Using newer planes is definitely better from a fuel use and emissions perspective. However, in Europe in particular where high speed train service is widely available, it would make far more sense for people to just switch away from air travel. Many of the trains are electric and even factoring in the energy source, the total well to wheel/wing emissions are much lower than flying. If you factor in the fact that train stations are typically in city centers, the total cost, time and emissions associated with train travel are far superior for the short to medium haul services on the continent.