ETG,

>>>how long it takes to fly over the Atlantic Ocean

FWIW, if you are crossing from the Northeast/Canada area, your crossing should take about 3-1/2 hours, on average. That's from coast out/feet wet to coast in/feet dry.

Of course, going down in Canada or Labrador could be a real challenge, too!

JMHO,
Mamabear

(PS) The PFDs onboard the aircraft are pretty good. You might not need/want to carry your own. Or you could take a couple of heavy duty balloons as a field-expedient flotation device.