Originally Posted by
CZAMFlyer
When overflying any jurisdiction, aircraft are not visually identified by their civil registration decals.
Air Canada can barely keep its fuselage & empennage decals from peeling, cracking or fading away; it doesn't need the hassles of more to look after.
Yes, it does (just the maple leaf roundel, not any text. Several other large airlines (Delta, Emirates, Virgin Atlantic, Qatar, Turkish, Aer Lingus all come to mind) preceded Air Canada in this regard.
Perhaps I should have been more specific. I am referring to the civil registration (such as C-GHPQ for fin 801) and not corporate logos.
As to Aer Lingus. I am familiar with almost every single airliner they currently have in use, particularly their Airbus fleet, and they all have their EI-XXX registration on the underside of the port wing near as practical to the wing tip. This location seems to be an industry standard. Can't really question any other examples you give but it's interesting that AC seems to have voluntarily elected to not have this optional identifier on their metal.
While it is true that airborne aircraft are not normally identified by their civil registration such identifier could be helpful in an emergency such as an airborne intercept because of radio and/or transponder failure or an accidental emergency squawk.
Additional info: Just checked Virgin Atlantic because I realised I had some small experience with them.
Looking at airliners.net, all the Virgin Atlantic metal in flight that had the underside of the port wing visible have the civil registration painted on them. Notably this included four of their 789 Dreamliners, G-VAHH, G-VDIA, G-VWHO and G-VZIG as well as the A330 G-VNYC.