With sweltering summer heat and long lines, no one can be happy about the latest Transportation Security Administration edict on powering up cellphones (and other devices) before heading to the gate at some overseas airports.

Sure, it’s another TSA “hassle,” but the new rule is for a deadly serious reason.

The Department of Homeland Security believes — based on sensitive information they’re not sharing with us — that al-Qaeda is still targeting America, especially passenger aircraft.

This time the terrorist tactic involves building a bomb into a cellphone or other electronic gizmo that a terrorist can carry undetected through security onto a U.S.-bound airliner.

No real surprise; This is just the latest in explosive al-Qaeda cabals.

Beyond the 9/11 hijackings, a shoe bomb (2001), explosive liquids (2006), an underwear bomb (2009), and modified printer cartridges (2010) have been used to try to bring down passenger/cargo aircraft.

Now TSA likely believes that, instead of being filled with “apps” and “selfies,” electronic devices could be packed with plastic explosives capable of punching a hole in an aircraft’s skin — with deadly results.

It seems that al-Qaeda’s best bombmaker, Ibrahim al-Asiri, is still dreaming terrorist dreams while holed up with Yemen’s al-Qaeda in the Arabian Peninsula, or AQAP.

If you can believe it, he reportedly implanted a bomb inside his own brother in a failed attempt to kill a Saudi official a few years ago. His brother was killed, but the target wasn’t.

This is the sort of evil we’re still up against.

What’s equally troubling is that news outlets report that AQAP may have joined forces with a Syria-based al-Qaeda offshoot, al-Nusra Front, to carry out an Asiri-inspired attack.

You’d think al-Nusra Front would already have its hands full with the ongoing Syrian civil war, including fighting the regime, Hezbollah and Iran as well as other competing terror groups like the ascendant Islamic State of Iraq and Syria, or ISIS.

But like ISIS, the al-Nusra Front has terror plans beyond the Middle East, including America. It has supposedly built camps for training foreigners to return to their native lands to conduct strikes.

It’s believed that a good number of Europeans and Americans have gone to Syria to fight. They have passports that might allow them to travel home — or abroad — schooled in the terrorist dark arts.

Plus, in a competition for foot soldiers, funding and fame, al-Nusra Front wouldn’t mind stealing the spotlight of savagery from its rival ISIS (of Islamic caliphate acclaim) and other violent extremists.

Think of it as terrorist one-upmanship.

The fact is that we’re facing the possibility of an AQAP bomb-making whiz joining forces with passport-packing foreign jihadists in distant Syria with the intent of bombing U.S. or other planes.

It’s a perfect storm of transnational terrorist teamwork.

This scary situation in the summer skies dictates that we take a good, hard look at our prevailing strategy for dealing with an increasingly complicated and challenging al-Qaeda threat — still going strong almost 13 years after the 9/11 tragedy.

 - Peter Brookes is a Heritage Foundation senior fellow
and a former deputy assistant secretary of defense.