These things are known as 'enhanced reality' displays. Much more practical
than HUDIS ( Fixed colimator projected head up display ) since in a
sailplane one needs to be looking about all the time.

I have seen a few at shows. Most are a complete waste of time in terms of
resolution, power drain and interface capabilities or are simply too large
to get onto your head with the canopy closed!

http://www.crd.ge.com/esl/cgsp/projects/er/

Ian