Q: Do the lithium-ion batteries pose an added danger?
A: Lithium-ion batteries are potentially more susceptible to fire because, unlike other aircraft batteries, the liquid inside of them is flammable. The potential for fire increases if the battery is depleted too much or overcharged. Boeing has built in special circuitry and other safeguards designed to prevent that situation. In September 2010, a UPS Boeing 747-400 crashed in Dubai after a large number of the batteries it was carrying as cargo caught fire.
Q: How much fuel does it save?
A: Boeing designed the 787 to use 20 percent less fuel than comparable aircraft. The Boeing 767-300ER consumes 1,600 gallons of fuel for each hour in flight. With jet fuel currently costing $2.91 a gallon, airlines could save $13,000 during the 14-hour flight between Boston and Tokyo. There is no public data yet on whether the 787 meets Boeing's fuel savings promises.
Q: Does any other plane use composites?
A: Composites are used in smaller amounts on most modern planes. Rival plane maker Airbus is designing its own lightweight composite jet, the A350, but that jet is still several years away from flying.
Q: Didn't it take Boeing a long time to get the 787 airborne?
A: Boeing applied to the FAA to make the 787 in 2003. The first plane flew in December 2009, and six test planes ran up some 4,645 flight hours. The first paying passengers took flight in October 2011, more than three years behind schedule.
Q: Why the delays?
A: Parts for the jet are made by 52 suppliers scattered around the globe. And, in a first for Boeing, large sections of the jet are built by these outside vendors and then joined together. That process, aimed at saving money, wasn't as smooth as Boeing had hoped. Parts weren't delivered on time, and the quality of some suppliers' products was poor.
Q: How much does the plane cost?
A: The 787-800 has a list price of $206.8 million, but airlines often negotiate discounts.
Q: How many passengers can fit on the plane?
A: It is designed to carry 210 to 250 passengers. Configurations vary depending on how many business-class seats and how much coach legroom each airline wants to provide.
Q: How many 787s are there?
A: Boeing has delivered 50 planes so far. Another 798 are on order. The company is ramping up production to build 10 787s per month in Washington state and South Carolina by the end of the year.
Q: Is it normal for a new plane to have problems?
A: Any complicated piece of machinery has glitches at first. The Airbus A380, for instance, had an engine explode midflight in late 2010. However, the unique nature of the 787's construction — and the increased media spotlight on this plane — have regulators doing a more thorough review.
Boeing insists that the 787's problems are no worse than what it experienced when its 777 was new in the mid-1990s. That plane is now one of its top-sellers and is well-liked by airlines.
"Every new commercial aircraft has issues as it enters service," Ray Conner, president and CEO of Boeing's commercial aircraft division, said Friday at the FAA news conference.
Q: What airlines fly the 787?
A: Japan's All Nippon Airways is the largest operator of the plane. United is the first U.S. airline customer with six. Air India, Ethiopian Airlines, Japan Airlines, LAN Airlines, LOT Polish Airlines and Qatar Airways also fly the plane.
Q: Where in the U.S. does the plane fly?
A: United Airlines is the only U.S. carrier to fly the plane. It flies between Los Angles and Tokyo and between various hubs such as Newark, N.J., and Houston and between Los Angles and Houston.
All Nippon Airways flies from Seattle and San Jose, Calif., to Tokyo. Japan Airlines flies from Boston to Tokyo, and LAN flies from Los Angeles to Santiago, Chile. Ethiopian started flying the plane to Washington's Dulles International Airport in late September but put a different aircraft on that route in mid-December.