I can't say I have a full answer but I think I do have some pieces of the puzzle.
Aien in Greek means 'Always'
Upsi means 'High'
Kratein means 'Master, Control, Conquer'
and
Petein means 'Fly'.
Both Aien upsikratein and Aien upsipetein are used in relation to modern - military - aviation, upsipetein also being used in other contexts such subjects related to birds. I have not found a translation to English - Google translate doesn't translate the words. But as said I have found both terms widely used. I therefore think the inscription on the stamp is deliberately Aien upsipetein.
An example of Aien upsipetein being used in a military context you will find here: https://ptisidiastima.wordpress.com/2011/11/08/%CE%B1%CE%B9%CE%AD%CE%BD-%CF%85%CF%88%CE%B9%CF%80%CE%B5%CF%84%CE%B5%CE%AF%CE%BD/
When you google in the Greek alphabet you'll find many more sites. All in Greek though. But you might want to contact these people to try and find out more. A particularly interesting site to contact because it uses both terms is: http://tro-ma-ktiko.blogspot.nl/2011/12/video_7810.html
The search terms in Greek would be αιÎν υψιπετείν and αιεν υψικÏατειν.
The Dutch education system comes to my rescue!
I'm happy to go with 'Always flying high' or 'always aiming high', as I gather there is a metaphorical meaning to υψιπετείν as well. I just didn't know πετείν - 'to fly'. (I imagine it is cognate either with 'pteron', a wing, or 'petalon', a leaf.)
All that just so that I can mount this stamp with the correct translation below! Perhaps SOR should adopt it as their motto as well!
Many thanks for your help, Gerben.
My pleasure. My guess would be that they used upsipetein so that the stamp addresses all fly boys instead of just those of the Greek Airforce.
αιÎν υψιπετείν
Actually, the Air Force motto is aien upsikratein, not upsipetein. However, the latter is what appears on the Greek stamp SG651, issued May 1st 1947, shown above.
The Air Force commander who coined 'aien upsikratein' ('Always dominate the heights', according to wikipedia), the motto on the Greek Air Force badge, was reinterpreting, or giving a modern twist to, what appears to be an ancient Greek saying - a saying so well-known that, although there are several references to it on the internet, I can find no modern translation. (The nearest may be something like 'aim for something spiritual'.)
The Ancient Greek dictionaries on the internet have never heard of it!
Personally, I think the stamp should read 'Always dominate the heights' (the English equivalent of the RAF's per ardua ad astra, or even 'Reach for the sky') - but it doesn't.
Any professors of Ancient Greek on SOR? Any Greek members?
re: That Greek Air Force motto - what does it mean?
I can't say I have a full answer but I think I do have some pieces of the puzzle.
Aien in Greek means 'Always'
Upsi means 'High'
Kratein means 'Master, Control, Conquer'
and
Petein means 'Fly'.
Both Aien upsikratein and Aien upsipetein are used in relation to modern - military - aviation, upsipetein also being used in other contexts such subjects related to birds. I have not found a translation to English - Google translate doesn't translate the words. But as said I have found both terms widely used. I therefore think the inscription on the stamp is deliberately Aien upsipetein.
An example of Aien upsipetein being used in a military context you will find here: https://ptisidiastima.wordpress.com/2011/11/08/%CE%B1%CE%B9%CE%AD%CE%BD-%CF%85%CF%88%CE%B9%CF%80%CE%B5%CF%84%CE%B5%CE%AF%CE%BD/
When you google in the Greek alphabet you'll find many more sites. All in Greek though. But you might want to contact these people to try and find out more. A particularly interesting site to contact because it uses both terms is: http://tro-ma-ktiko.blogspot.nl/2011/12/video_7810.html
The search terms in Greek would be αιÎν υψιπετείν and αιεν υψικÏατειν.
re: That Greek Air Force motto - what does it mean?
The Dutch education system comes to my rescue!
I'm happy to go with 'Always flying high' or 'always aiming high', as I gather there is a metaphorical meaning to υψιπετείν as well. I just didn't know πετείν - 'to fly'. (I imagine it is cognate either with 'pteron', a wing, or 'petalon', a leaf.)
All that just so that I can mount this stamp with the correct translation below! Perhaps SOR should adopt it as their motto as well!
Many thanks for your help, Gerben.
re: That Greek Air Force motto - what does it mean?
My pleasure. My guess would be that they used upsipetein so that the stamp addresses all fly boys instead of just those of the Greek Airforce.