Still under negotiation is the sale to Pakistan of the larger Chengdu J-10B, a modernized version of the canard-delta J-10. Although Pakistani interest in the J-10 has been reported since 2006, no firm deal has been announced. The most recent reports suggest that China has offered a squadron of J-10Bs. The new version differs from the original in featuring an AESA radar, IRST, a diverterless inlet and underwing fairings that point to an improved electronic-warfare suite.

Unlike the JF-17, neither the J-10 nor the J-10B has been demonstrated outside China. The J-10B's existence is known only via Internet leaks, but its existence makes the J-10 look like a sunset program. Also, the production of the J-10 still depends on Russian engine supplies.

China has ordered a total of 399 AL-31FN engines from Russia, according to Stockholm International Peace Research Institute data; its most recent order, for 123 engines, was placed last year. Of those, 276 had been delivered by 2011. Most of these power 220-plus J-10s, but others have been used in the Shenyang J-11B and J-15—the “bootleg” versions, respectively, of the Su-27 and Su-33. The indigenous WS-10A Taihang engine is under development and reported to be under test on J-10B and J-11B prototypes, but the 2011 order, covering four years of J-10 production at the rates seen so far, suggests that full production quantities of the WS-10A are not expected until 2015.

Technologically, the J-10B may be a stepping-stone to the J-20 and J-31. The status of China's stealth program has not become much clearer since the surprise appearance of the heavyweight J-20 at the end of 2010. However, the unveiling of the smaller—roughly Joint Strike Fighter-sized—J-31 points to the two designs being complementary, rather than alternatives. Despite their different shapes and sizes, the J-20 and J-31 are similar in that they appear to have advanced beyond the stage of being pure technology demonstrators. Both are larger than the J-10, pointing to a future three-level force mix.

In the next few years, the pace of Chinese fighter development may be set by the resources available and the sheer number of programs. In 2005, China had three major fighter projects underway: the JF-17, J-10 and J-11B. Today, it has the J-10B and J-15, and both Chengdu and Shenyang have challenging stealth programs.

An older fighter that apparently remains in production is the Chengdu J-7, developed from the MiG-21, but with changes including a double-delta, slatted wing and new canopy. In 2011, the Bangladeshi air force announced that it would be taking delivery this year of a squadron of 15 F-7BGI fighters, equipped with a three-screen glass cockpit, head-up display and hands-on-throttle-and-stick controls. These will begin to replace the mixed force of older F-7s, A-5IIIs and MiG-29s.