"Aircraft that are on these instrument approaches may be approximately ¼-mile east of the current MENLO waypoint when they pass over East Palo Alto," an FAA spokesperson stated in an email.

The FAA updated the San Francisco arrival route known as SERFR to improve safety and operations. Now called SERFR3 -- for the third iteration of the route -- the path is taken by planes flying up from the south and inland from the coast, crossing the mountains near Santa Cruz and over Palo Alto, Menlo Park and East Palo Alto before heading north to San Francisco International Airport.

Aircraft noise opponents have sought to move the MENLO waypoint near the border of Menlo Park and East Palo Alto or have planes fly over at a higher altitude as part of requested revisions to the FAA's NextGen program, a modernization of the air-travel system mandated by Congress.

The FAA did raise altitudes for flights at certain points west on SERFR3, where planes from the south cross land after flying over the Pacific Ocean, an agency spokesperson in an email.

Jets coming in to airports must fly on routes and at certain altitudes by reaching specific "waypoints" along the path. The entire SERFR3 travel path is within the highly controlled, existing Class B airspace around San Francisco International Airport. Classes of airspace can be restricted to certain uses -- such as commercial or military -- and pertain to spaces between certain altitudes in which planes may fly.

Planes flying along the SERFR3 route will be allowed to glide rather than have to throttle back to slow down, which creates more noise. Known as an optimized profile descent, it is no different than how planes fly using the current SERFR2.

The SERFR3 update is unrelated to the proposal to return flights to the Big Sur arrival route, which is part of a potential revision the FAA is looking into to ease noise issues, the FAA stated.

Even with flight routes such as SERFR3 , air traffic controllers occasionally decide to send some aircraft off the published SERFR3 and instrument approaches for safety and sequencing purposes, according to the FAA. This can happen when flights stack up on their approach to the airport, for example.

SFO airplane route changes slightly

Planes may now pass over East Palo Alto -- a quarter-mile east of the MENLO waypoint