Thank you for replies. Here are some general comments for them:
The main idea of these repaints is a virtual advertising of the countries and the airports/cities. The reason that stand behind this idea is, every HUBs have its own 3-4 pieces of 747s, that have fix, far destinations around the world. So 1 of these aircrafts could be an advertising aircraft to each HUB.
Language idea:
As EuroHarmony's main language is English, and the advertising text is very easy, I think English could be used for all variants.
National flag idea:
As the colors mainly represents the colors of the flag, I do not think a separate national flag should placed on the plane too.
LGAV question:
Its very simple

The airports name is too long, and the tower image is too much to the right... but I can change it.
The colors questions:
I tried to use colors that represent the countries national flag, or represents colors, that are very unique in that country. Also a pic of the local control tower connects it to the airport again. Detailed:
EHAM: As many countries have blue-red-white flag, I wanted to add another feeling: The orange, which is a unique color in the Netherlends...I have to say I do not know the historical background behind this

I know its a very strong orange, but this is the tone that many of you choosen monthes ago.
EGLL: This is the country where the national colrs are really the blue-red-white, just as in the national flag. Maybe the red is too much, but again, its a very strong red, that I think somehow connects with UK.
ESSA: No question, 2 colors from the national flag, I think this is very easy to understand.
LGAV: Again the 2 colors of the national flag: blue and white. The blue is a darker sky blue, which you can see on many pictures correspond Greece.
LPPT: It was a hard one, as the flag contains claret, gold and green. The main color is the claret, because of the wine. I am not sure if this tone is the original on the flag, but the national football team uses always this dark color. The sun simulates the gold...but no green. If you have better idea, I am open for that.
LSZH: The other hard one. Red and white in the flag, but the only thing I could think about Switzerland is the Alps and Milka chocolate. Snowy Alps represents the white, and the tail shows red. Again, if you have better ideas, then its appreciated.