The law, which was signed into law by Republican Gov. Greg Abbott, also does not require gun owners to get a background check.
The officer was stabbed on the scene of the incident, which triggered a lockdown.
The GOP congressman said he mistakenly put the unloaded handgun in his carry-on rather than his checked bag.
The National Shooting Sports Foundation says David Chipman is a threat to the gun industry.
"Dude has his solar panels aimed to the moon," goofs a critic on Twitter.
Teachers in Ohio would have to complete a police training course or have 20 years' experience as a peace officer to carry a gun.
A judge had argued earlier this month that AR-15 guns were like Swiss Army knives, "good for both home and battle."
Mark McCloskey, who pleaded guilty to pulling a gun on Black Lives Matter protesters, posed with a new AR-15 gun after surrendering his old one.
People age 21 and up will no longer have to obtain a license, complete training or undergo a background check to carry a handgun in public.
According to a fundraiser for Jemil Evans, his friend had just received his license to carry and was excited to show him his new gun.