A given flight consumes much fuel and produces many carbon emissions. However, you then need to consider the fact that the plane is carrying perhaps hundreds of people, as well as cargo, long distances. Imagine if each of those people on a plane drove a car instead. A fully-loaded long-haul flight is probably better for the environment than driving is.
Having flight as part of our economy does mean high altitude pollution. However, if everyone had to travel by land or sea, there would be far more land-level pollution, which is worse. That means that air flights are the least damaging option currently available to us without crashing the whole economy.
Overall, putting multiple passengers on one large craft causes less pollution than all of those people operating smaller vehicles. So yes, like trains and buses, there are many environmental benefits to flight. I think this all needs to be considered for the long term health of our planet. It's in dire straits.
I have my doubts there are environmental benefits to flight. These planes burn fuel, so planes are not inherently environmentally friendly. Flight is more about convenience for humans. Traveling from continent to continent is impossible otherwise unless taking the time to ride a boat across the ocean. Flight shouldn't be considered environmentally friendly, its use and purpose has nothing to do with the environment.