Oops! The agreement that lets American planes fly over Russia just expired

As the United States and Russia face off over Syria, the agreement that lets American planes fly through Russian airspace has just expired–and currently there’s no plan to reinstate it.

As Bloomberg reports, the U.S. and Russia haven’t had a permanent agreement regarding use of air space since 2001. Instead, every six months or so they renegotiate permissions, although recently Russia has “begun offering renewals for shorter, more arbitrary periods depending on the airline,” according to one U.S. official who spoke to Bloomberg. Now with tensions rising and sanctions flying more freely than airplanes, the meeting between the U.S. and Russia to renegotiate air space deals has been canceled.

Russia has said it will allow flights to continue while the two governments work to reschedule the meeting. U.S.-based airlines have already warned that they may need to reroute–or even cancel–some flights if a deal is not made soon.