It really isn’t. More Kerosene is burnt in lamps and cook stoves in rural Africa and Asia than in the global aviation industry. Moreover, airlines have a capitalistic incentive to reduce carbon emissions already, since fuel is one of the largest costs they bare and the only one easily reducable.
Aviation is a tiny fraction of global travel emissions. It’s mostly road vehicles. Aviation is 11% of transportation which is 30% of global emissions. It’s a tiny fraction, considered.