NEW YORK -- The National Rifle Association, and now the State of Florida, faced a growing backlash Saturday as companies cut ties to the gun industry following the latest school massacre, and student survivors called for tourism boycotts of their home state until gun control measures are enacted.

The latest companies to end their ties with the NRA were Delta and United Airlines, two of the three largest U.S.-based airlines.

Corporate ties to the NRA aren't the only elements undergoing scrutiny in the wake of the Valentine's Day shooting at Marjory Stoneman Douglas High School in Parkland, Florida, where police said 17 people were killed by a 19-year-old former student who entered a freshman building and began firing an AR 15 assault-style rifle. Broward County Sheriff Scott Israel said he's investigating claims that some Coral Springs police officers saw several deputies outside the building after the shooting began.

On Thursday, Scot Peterson, the school's resource officer, resigned under fire from the Broward Sheriff's Office for failing to enter the building. The sheriff told news outlets he will investigate the claims that other deputies didn't enter the building.

On Saturday, both Delta and United said Saturday they will no longer offer discounted fares to NRA members to attend their annual meetings, and both have asked the gun rights group to remove any references to their companies from the NRA website.

A growing number of large companies have announced they are cutting or reducing ties with the NRA. Rental car company Hertz will no longer offer a discount program to NRA members and First National Bank of Omaha said it will not renew a co-branded credit card it has with the NRA. Most of these companies do promotional tie-ins with groups to spur customer loyalty to NRA members, and do not receive money directly from the NRA.

The moves have come as petitions circulated online targeting companies offering discounts to NRA members on its website. #BoycottNRA was trending on Twitter.

In an email Saturday, the NRA called the companies' actions "a shameful display of political and civic cowardice" and said the loss of corporate discounts and other perks "will neither scare nor distract" NRA members."

"In time, these brands will be replaced by others who recognize that patriotism and determined commitment to constitutional freedoms are characteristics of a marketplace they very much want to serve," the NRA statement said.

The State of Florida was also facing a potential boycott and backlash as well. One teen survivor of the Florida school shooting suggested on Twitter Saturday morning that tourists stay away from the state during spring break; he got immediate response on social media.

"Let's make a deal," David Hogg, a Marjory Stoneman Douglas High School student who has been a major player in the .neveragain movement, tweeted. "DO NOT come to Florida for spring break unless gun legislation is passed."

Wendy Glaab, 60, of Fonthill, Ontario, Canada, was among the first to respond. "I like many Canadians travel to Florida from time to time to escape our winter. I can't speak for others but I will not be returning until meaningful gun control legislation is in place."

Glaab told The Associated Press on Saturday that her sister owns property in Fort Lauderdale and she is able to visit any time she chooses.

Members of the NRA have access to special offers from partner companies on its website, ranging from life insurance to wine clubs. But the insurance company MetLife Inc. discontinued its discount program with the NRA on Friday. Car rental company Hertz and Symantec Corp., the software company that makes Norton Antivirus technology, did the same.

Insurer Chubb Ltd. said it is ending participation in the NRA's gun-owner insurance program, but it provided notice three months ago. The program that provided coverage for people involved in gun-related incidents or accidents had been under scrutiny by regulators over marketing issues.

Those defections arrived after car rental company Enterprise Holdings, which also owns Alamo and National, said it was cutting off discounts for NRA members. First National Bank of Omaha, one of the nation's largest privately held banks, announced that it would not renew a co-branded Visa credit-card with the NRA.

Other companies, including Wyndham Hotels and Best Western hotels, have let social media users know they are no longer affiliated with the NRA, though they did not make clear when the partnerships ended.

The swiftness of the corporate reaction against the NRA has differed from that of past shootings, including the 2012 Sandy Hook Elementary School massacre that claimed 26 lives and the killing of 58 people in Las Vegas last fall, said Bob Spitzer, a political scientist at SUNY Cortland and a scholar on gun politics. Spitzer said the reaction was likely a reaction to the student mobilization that followed the Florida shooting, but he said it was too soon tell how significantly it will sway the country's wider gun debate.

NRA Executive Vice-President Wayne LaPierre said this week at the Conservative Political Action Conference that those advocating for stricter gun control are exploiting the Florida shooting.

President Donald Trump has aligned himself with the NRA, suggesting some teachers could be armed so that they could fire on any attacker. However, Trump has also called for raising the minimum age for purchasing semi-automatic rifles, a move the NRA opposes.

AP Reporter Freida Frisaro contributed to this report from Fort Lauderdale, Florida.