Yes
They're threatening to blow up an airliner or actually doing so to hit the news. 911 terrorists had blades, bomb jackets (whether these things are actual doesn't matter, saying you have them is enough), and eventually destroyed the tallest towers in NY and part of Pentagon and erased themselves while committing the crime
The point of terrorism is to be visible, dramatic and cause teror. It's not to get a stealth award for hacking the coupon system at the shop and get away with it
A bomb (real or not) planted by terrorists or hijackers is meant to be eventually known one way or another. It's the point