Transportation CO2 emissions make up a tiny fraction of total greenhouse gases. Water vapour is by FAR the biggest greenhouse gas. I wonder if a 787 burns more hydrocarbons flying 250 people from NY to LA than 250 cars driving that distance? Roughly ~9000gal (2500mi 787 @ cruise) is 36gal per car. Assuming everyone gets perfect highway mileage even if they're Prius it wont get them the whole way (50MPG*36gal=1800mi). And that's not considering the energy required to build and maintain 250 Prius cars vs. the cost of one 787. The retail cost alone for 250 Prius is nearly $90M. A 787 is more like $250M, but lasts a least 3x longer than a car.

Transportation has improved since the 1960 by a HUGE amount. Modern cars, trains, and airplanes are significantly better (safer, cheaper, more efficient) than those in the 1960s. I'm curious how much travelling you did in the 1960s compared to today?