http://www.telegraph.co.uk/news/worldnews/middleeast/yemen/8542813/Yemen-president-launches-air-strikes-as-rebels-advance-towards-Sanaa.html
Unlike Libya, which was under arms embargos for close to 20 years, Yemen has a fairly modern air force mostly consisting of Soviet built fighters, along with 45 of the American built F5E, the workhorse of the developing world. Probably more important, they have a state of the (Russian) art mobile anti-aircraft weapon network.
We’re officially playing for all the marbles. NATO now has to seriously worry about attacks on their flank, especially if Russia decides it wants a fight.