The list of companies choosing to boycott the National Rifle Association (NRA) – under pressure from gun control activists – is growing daily. Saturday, two of the largest airlines in the world joined the list (see more names below).

Delta and United have announced that they will be cutting ties with the NRA. The growing movement to boycott the NRA comes after the tragic shooting at Marjory Stoneman Douglas High School in Florida. Activists note that the alleged 19-year-old gunman, who killed 17 people, used a legally purchased AR-15 rifle.

The Washington Post reports: Without context, the airlines’ twin announcements on Saturday morning might look trivial: The end of flight discounts to the NRA’s annual convention, which few outside the gun rights organization likely knew existed before they became boycott targets.

But in abandoning the NRA, the airlines followed car rental giants Avis, Hertz and Enterprise, the Best Western hotel chain, the global insurance company MetLife, and more than a dozen other corporations that have severed affiliations with the gun group in the last two days.

While it’s unclear what effect the corporate snubs will have on the NRA, they have given the nascent #BoycottNRA a string of rapid, prominent victories and exposed vulnerabilities in a gun rights lobby that had seemed untouchable less than two weeks ago.