What is this red dashed line between door and cockpit window? I noticed this dashed line located between the door and cockpit window on this 737-300 while boarding this exact aircraft at Ibiza airport. It seems to have text beside it but I did not have time to read it while boarding and it is too hard to read from the photo. Older photos of the aircraft with the same paint job do not have this suggesting that it was added recently. Wondering if it has anything to do with aligning air stairs or jet bridges. Does anyone know any other aircraft with a similar marking?


(Photo by Roberto Bianchi, source)
(Source: airliners.net)

The letters read 'air bridge'. The line is used for docking with the air bridge as you suspected. Also see: What are these markings under the passenger door?


  (...) the position of the alignment marks are not standardized and are carrier specific.


It also appears on the silver livery:


(Source: planespotters.net)



It reminds me of this:


(Source: wikimedia.org)