The airline company Ansett, which is currently dying or about to be resurrected, depending on who you believe, had a very good flag based on the Australian flag. It had the Ansett logo (consisting of a yellow A-shape without the cross bar, the right arm thicker than the left, with a white seven pointed star nestled against/into the right arm at the bottom), at the hoist, with the star roughly in the position of the commonwealth star on the Australian national flag, and the southern cross in the fly as in the Australian national flag. In my opinion it was quite a good corporate flag. However, I have always found it interesting the way that the older, "establishment" airline,Qantas, has the symbol that is part of many people's idea for a new national flag (and makes some people say the proposals look too much like an airline flag), whereas the newer airline has the symbol using elements of the current national flag, and a flag which is very similar.
In my humble opinion, the flag looks even better when flying, when the contrast between the two shades of blue is less distinct. There is a nice photo here.
This design was also used by Ansett as the logo on the tails of the aircraft. Before this logo was adopted, the Australian national flag itself was used on the tails. The Ausflag site contains a speech by Frank Sartor (then Lord Mayor of Sydney) which quotes Ansett's marketing director saying that the change was due to marketing research on how the flag logo was not perceived as Australian in the Asian market.
When Ansett went broke a few years ago, after the final flight the staff performed a little "ceremony" in which they folded an Ansett flag while the Last Post was played, in the manner of a military funeral. This generated a little controversy back then, as some people considered it disrespectful to "mock" the war dead.