It's not illegal, period, because this isn't a regulated security. Prediction markets don't fall under these laws; in fact, insider trading is seen as a feature of these markets.
They took off from many different places so you'd have to somehow know that ~150 aircraft were taking off. If you happen to just see one spot, you'd likely just assume it was another bombing of a boat or a dock.
Or… someone seeing a bunch of commercial flights over the Caribbean getting cancelled. Could be anyone from airline ops to frustrated travelers stranded in Boston.
I guess... but I still think first thought would be just some more bombing. It's a big step to go from bombing boats, a dock, arresting and extraditing a foreign leader in the middle of the night.
I highly doubt that that's the case, given that taking a large and publicly visible financial position based on confidential information still amounts to disclosing information.
But it's obviously also ripe for abuse. Any govt. employee can start trading on the side, 100% untraceable.