The Pentagon maintains that it does not expect either of China's fifth-generation fighter programmes to become operational before 2018.
"We do not expect either the J-20 or the J-31 to achieve an effective operational capability before 2018," says David Helvey, the deputy assistant secretary of defense for East Asia. "I think both the J-20 and the J-31 are still in the prototype phase, actually, and so we haven't seen them participate in training or exercises," he adds.
Helvey says that China is emphasizing the development of its fighter capability and is making progress. "With respect to China's fighter aircraft, China continues to -- to emphasize and prioritize building modern and more capable fighter platforms," he says.
Helvey notes that the Shenyang J-31 flew within two years of the Chengdu J-20's first flight in January 2011. "The first J-31 flight test in October 2012 highlights China's continued ambition to produce advanced fifth-generation fighter aircraft," Helvey says. "And I think we'll still have to monitor China's development of a J-20 and potentially the J-31, as fifth-generation fighters."
Chinese naval aviation is also making progress with the Shenyang J-15 starting to operate from the carrier Liaoning in November, but the Pentagon expects it will be sometime before China has an operation carrier capability. "We anticipate that China will spend the next three to four years on training and integration before achieving an operationally effective aircraft carrier capability," Helvey says. "China will likely build several indigenous aircraft carriers over the next 15 years."