The visual identity for easyJet is far different than that for Etihad for well-thought-out reasons.
easyJet is part of a larger British/European brand called easyGroup. Economy, informality and simplicity are stressed.
Etihad is headquartered in Abu Dhabi. Their brand stresses formality, elegance, service and alludes to the Arabian Desert and Arabic culture.
They’re very different brands with very different goals and for very different reasons.
Personally, I don’t care for the visual identity of either all that much, but a redo of easyJet to look more like Etihad would not be appropriate.
The entire easyGroup brand is well established and well-known. There is lots of brand equity in the easyGroup brand and the look has an appropriate personality for the company. Their use of Cooper Black makes it a little dated, but it works for them. easyJet and the entire easyGroup brand are in the enviable position of having developed a famous brand that is worth a fortune in recognizability.
Etihad Airways is much less known. They’ve developed a formal, higher-end look because the owners want a different personality for their airline that contrasts with their already established and larger competitors. Personally, I’m not a fan of Etihad’s typography, but that type needs to mesh well with the Arabic script that’s also used. The gold color they’ve chosen plays into the personality they’re trying to achieve and also has a cultural relevance to the Arab Emirates where they’re based.
I will say, though, that Landor (the San Francisco design firm) that created the Etihad visual identity did a superb job — as they always do — in researching the goals and personality of the company and imbuing them into the visual identity of the airline. I’ve visited Landor’s offices a few times and have worked with their former creative director. They’re one of the best in the world for their particular niche in this industry.