Yeah, producing any old electro magnetic pulse is not hard. Producing one that is powerful enough to weaponize IS hard. Much harder than that article suggests. They have not already been developed. Not one that is of any military use. What has been developed and is still being worked toward fielding are directed microwave weapons. The article reads like ones on flying saucers. They bring up the reality of electric thrusters and then totally gloss over or ignore the fact they are completely impractical and don’t have enough power to lift anything useful. Instead that just allude that since the principles were discovered many decades ago the some secret program must have made them workable by now. Anyway, if it had been any sort of EMP the display systems would have almost certainly rebooted and they didn’t.
How fast would the systems have rebooted? Remember, the co-pilot first noticed a problem 40 seconds before planned landing. And we don’t actually know that the systems didn’t start rebooting, either just before or just after the landing.
Like I said, I don’t really think this was an EMP, but I do think al Qaeda, with its vast money and expertise, is capable of producing an EMP weapon that could do this sort of thing, though perhaps with unreliable results — i.e. a reliability level that wouldn’t be acceptable for military or law enforcement use, but would be acceptable if your only purpose is to wreak havoc in the Western world. Something highly unreliable would surely be easier to build, and thus some into existence sooner, than something reliable.