They are the the standard trading card size: 2 1/2 X 3 1/2.
On the back, there's what seems to be a logo that says : BOEING 1916 1991 75YEARS
On the back of each card are a few paragraphs of information and specifications.
for example : this card specifically says :
The Boeing 757 is a new twin engine, short-to-medium-range which combines an efficient six-abreast seating fuselage with a new-technology wing and engines to give the best fuel mileage of any commercial airliner. Fuel efficiency of the new airliner was a very important design goal, and the 757 meets that objective. It is up to 80% more fuel efficient than the airplanes it replaced.