United and Delta airlines joined a growing list of companies to reject the gun advocacy group after it hit out against a student-led campaign for tighter gun laws.
In tweets on Saturday, both airlines said they were ending discounts for NRA members.
It comes after the NRA lashed out at campaigners advocating gun control, saying they were exploiting the mass shooting to promote an anti-gun agenda.
Former student Nikolas Cruz killed 17 people at the Marjory Stoneman Douglas High School in Parkland on February 14, using an AR-15 assault rifle he had purchased legally.
Other firms dropping the NRA include rental car brands Alamo, Enterprise and National.
All are owned by Enterprise Holding which said it was ending discount programmes. Another car rental firm, Hertz, also said it was ending discounts.
First National Bank of Omaha said it would not renew the NRA-branded credit cards, while insurance firm Chubb Ltd said it would stop underwriting a NRA-branded insurance policy for gun owners.
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Last week NRA leader Wayne LaPierre used his address to the conservative conference CPAC to lash out at anti-gun campaigners, claiming Democrat politicians and the national media were eager to blame the NRA for the tragedy.
