Some teams do and some don't. If a team has a strategic plan and builds the airline in accordance with that plan, they may have losses for 3-5 quarters. However, you should not take any loss lightly. You should know WHY you have losses. Is it because you have priced yourself too high above the competition or is it because you have additional expenses as you open new markets, etc.
Various professors have different things they are looking for.
As a matter of course, we have seen an equal number of teams win that were discounters, luxury, and regular airlines. There are good airline industry cases in several strategic management textbooks such as Miller and Dess, Strategic Management, 2nd Edition. In addition, most cases about airlines themselves have good industry overviews. You can also look at the home pages of some airlines. For example, Southwest Airlines or American Airlines have informative home pages.