Transatlantic vs. N. Cape Coastal Traffic

On a Wednesday night from about 9pm to 10pm there were more airplanes going by than cars, on the Transatlantic Jet Route versus the North Cape Coastal Drive. About 12 planes passed while sitting by the fire outside, only about 5 cars went by.

Some of the planes in the sky were traveling in pairs, with a smaller flashing light on one. I wonder what's that all about?