It's pretty obvious that you don't know it, but you have no idea what's going on with this subject matter.
It's pretty obvious that your mental capacity can't stretch beyond a single sentence, if you want to get personal.
There are loads of extremely dangerous exploits that could occur, even offline, if a pilot's iPad was hijacked. Theoretically, they could develop a baseband firmware which jammed the on-board GPS and other communications and, since these are the backup maps, they could have the plane fly in the wrong direction to engineer a low-fuel situation either in a compromised location (taking the aircraft, crew and passengers hostage) or just in the middle of the ocean. Maybe they can transmit a convincing dummy GPS signal. The iPad doesn't even have to stay offline - the hack could potentially invisibly connect to on-board WiFi if available. Maybe they don't even have to - maybe they can just detect flight conditions in other ways and make the iPads overheat and explode. There are players out there who truly go to incredible lengths; never underestimate the lengths people will go to in order to harm others.
It's pretty obvious that you severely underestimate cybersecurity.
Relax buddy. iOS devices have been hacked/jail broken for years now. I haven't heard of any major catastrophic issues because of it, have you?
A zero-day exploit is fundamentally separate from the concept of "jailbreaking". Jailbreaking is something you do to your own device, with the intention of removing restrictions from the manufacturer. A hack is something that somebody else does to invade your computer, and their intentions can be all over the map. Both may make use of zero-days, but there is an huge distance between them.
I do remember hearing about cases where malware jailbroke peoples' phones. There are some proof-of-concepts, but I also remember about hearing one in the wild at one point (forget the name).
Here's a POC fake charger which can jailbreak your phone without you knowing:
http://www.jailbreakmodo.com/3rd-party-iphone-chargers-can-install-malware-on-your-device.html
Also cases about malware targeting jailbroken phones:
http://researchcenter.paloaltonetwo...000-apple-accounts-to-create-free-app-utopia/
This is why I find the idea of zero-day exploits available for anybody with enough cash abhorrent. I'm aware that such places likely exist on the darknet, but we shouldn't allow them to also openly flaunt themselves as a registered corporation. We don't have a way to regulate their use (if there are legitimate ones) by private parties, so we must consider them potentially extremely dangerous.