It's not enough for Yemen's skies to fill up with armed U.S. drones. Now the Pentagon wants to buy its Yemeni ally small, piloted spy planes. It's a sign that the U.S. is upgrading the hardware it gives the Yemeni military, and digging in for a long shadow war.

That's the upshot of a recent U.S. military message to the aviation industry. The Navy asked earlier this month for 25 "Light Observation Aircraft" – small, two-seater Cessna-style planes, good for short-range reconnaissance over, say, a patch of land that an al-Qaida affiliate is trying to overrun. That's in addition to all of the American remotely piloted aircraft that already fly over Yemen, which has become the hottest undeclared battlefield in the global U.S. drone campaign.

The planes have to be configured so the U.S. can teach Yemenis how to be their own eyes in the sky, and they need to be in Yemen in under 24 months. "Austere environment landing/takeoff capable" is a must. The push for the aircraft is somewhat reminiscent of the Pentagon's "Project Liberty" crash program to rush small, relatively cheap Beechcraft planes to the Iraq and Afghan warzones so troops could trick them out with advanced sensors and cameras. It remains to be seen if that's in the works for Yemeni pilots.

After a brief pause prompted by Arab Spring instability, U.S. defense assistance returned to Yemen this summer in a major way. But while the U.S. has been generous – $112 million this year, or about as much as the U.S.' post-9/11 military assistance totaled by 2010 – it's not bought Yemen many high-end systems. Small Raven drones, radios, night-vision goggles, rifles and ammo, ruggedized "raiding" boats and other hallmarks of unconventional, commando-style tactics have been the norm. Manned spy planes are certainly good for unconventional wars, and they also represent something of an upgrade.

The U.S.' shadow war in Yemen is showing other traces of entrenchment and durability. In September, the Army put out a call for armored SUVs, the signature vehicle of the post-9/11 era for transporting security contractors and operatives who'd prefer not to be seen taking military transport. Starting in January, transiting diplomats once lodged in a Sanaa hotel run by the Kuwaiti government will now stay in a secured "hotel-like" domicile constructed by the State Department, separate from the U.S. embassy and complete with "30-plus channel hotel cable system" and room "for up to 240 guests." (Hmm.)

All this gives substance to Defense Secretary Leon Panetta's warning last week that the U.S. should disabuse itself of any notion that the war against al-Qaida was wrapping up. (Never mind that such notions were once spread by Leon Panetta.) Panetta wants to wage those wars whenever possible through foreign governments like Yemen's, bolstering their capability to fight so that U.S. troop presences can be minimal. Now Yemeni pilots will be able to see just how long that war stretches over their horizon.