prototype flypast climbing after take-off. (Photo by: aviation-images.com/UIG via Getty Images)

United Airlines' latest aircraft order comes with a rare perk in an age of increasingly cramped commercial flights: more space.

The cabins of the 25 regional Embraer E-175 jets that United agreed to buy this week, an order worth more than $1.1 billion at list prices, are seven inches wider with ceilings that are almost five inches higher than the old Bombardier regional jets they'll replace, according the companies. United said they will have 70 seats aboard, even though 76 seats could fit.