Do you have a pet snake? If so, you may have some idea what it's like when the airlines lose your bag. I'll explain - once class is underway.

Yes, today we grade the airlines for on-time flights, lost luggage (or as the airlines so amusingly put it, "mishandled" baggage) and complaints about airline service. You may be surprised; in some categories, the airlines are showing significant improvement, yes, even when it comes to lost bags. But I'll show you the numbers so you can see for yourself.

First things first: which carrier gets you where you need to go on-time?

Airline On-Time Performance: C

If you have to fly but don't have time for delays, you want Hawaiian Airlines. For the past six years, it's held the top spot for on-time airline performance according to the monthly numbers amassed by the Bureau of Transportation Statistics (BTS). Since the most recent stats cover June 2011, that's the month we'll examine here, and Hawaiian has ruled June (and most other months) since 2005. In fact, this past June, its flights were on-time more than 93 percent of the time.

Well, of course Hawaiian is number one! The weather is great in Hawaii and the bulk of this carrier's flights, more than 85 percent of them, are inter-island hops. The number two spot is more interesting: for the past few years, Alaska Airlines has dominated June. In third place this year: Southwest, but there's a lot of movement here; best on-time performance in June 2010 was US Airways and it was ExpressJet in June 2009.

Worst on-time performances: June 2011 offenders included both US Airways and ExpressJet, which only goes to show some years are better than others. The honor for very worst went to Atlantic Southeast (on-time only 66 percent of the time). You'll typically see a lot of regional carriers in the "worst list" but American Airlines made the cut in June of 2009, 2008 and 2007.

By the way, if the airlines continue to cut capacity as has been suggested in the wake of the latest economic downturn, on-time performances should improve thanks to fewer flights (although the recent alleged pilot sickouts at Continental and US Airways aren't exactly helpful).

I mentioned weather just a moment ago and in fairness to all these airlines, it must be said that bad weather caused more than a third of all these June flight delays (yes, summer storms often cause more delays than snow). Not much you can do about the weather, unfortunately.

Collectively, I give the airlines a "C" grade for on-time performance, mainly because the percentage of on-time arrivals is on the rise, though it could be better. Take a look:

• June 2011: 76.9%

• June 2010: 76.4%

• June 2009: 76.1%

• June 2008: 70.8%

• June 2007: 68.1%

One reason for the improvement may be that there are fewer airlines to be late: back in 2007, there were 20 airlines reporting their stats to the BTS but thanks to mergers such as Delta/Northwest and bankruptcies (ATA, etc.) this year just 16 airlines reported.

Lost Baggage - C-Plus

Now let's talk bags, either lost for good or temporarily misplaced. In June of this year, the total airline mishandled baggage rate was 3.57 reports per 1,000 passengers. That may seem like a lot but it's roughly equivalent to the number of Americans who have a pet snake in their household (1 in 333, per the Book of Odds) and how many people do you know with a pet snake? The best numbers for June of 2011 were posted by (in order) AirTran, JetBlue and Frontier; the worst were American Eagle, Mesa and Atlantic Southeast.

Now let's look at previous bag loss numbers:

• June 2010: 3.65 reports

• June 2009: 4.17 reports

• June 2008: 5.15 reports

• January-June 2007: 7.34 reports

Definite improvement! My impulse is to give the airlines a collective "B-minus" grade for bags, but I since I know how painful lost luggage can be, let's compromise with a "C-plus".

Air Travel Complaints: C-Minus

Finally, we get to complaints, but only those that are reported to the Department of Transportation; I think most of us would go directly to the source - the airlines - with our complaints and only turn to the DOT as a last resort, so bear that in mind. By the way, the DOT has made it easier than ever to file a complaint should you want to.

This past June there were 1,127 complaints to the DOT about air travel and most were directed at the big four: American, Delta, United and US Airways which makes sense since they have more flights than most airlines so there are more opportunities for things to go sour. On the other hand, Southwest was number one in domestic passengers for the first five months of the year (Delta was number two), and Southwest had only 34 complaints compared to Delta's 109 complaints.

Is Southwest that much better, or do the loyal fans of the no-frills airline simply have lower expectations? I'll give Southwest a "B" grade (you get an "A" for zero complaints), but overall, the airlines get a "C-minus".

Here are the numbers for air travel complaints in recent years:

• June 2011: 1,127 complaints

• June 2010: 1,423 complaints

• June 2009: 747 complaints

• June 2008: 881 complaints

• June 2007: 1,097 complaints

Couple of questions: Do the number of complaints reflect reality or are passengers just too beaten down to bother? And, am I too generous when it comes to grades? Perhaps, but I also recognize the airlines are in a struggle for survival these days, and like the rest of us, are trying to do more with less. I'll cut them some slack - for now.

Rick Seaney is one of the country's leading experts on airfare, giving interviews and analysis to news organizations that include ABC News, The New York Times, the Wall Street Journal, Reuters, the Associated Press and Bloomberg. His website, FareCompare.com, offers consumers free, new-generation software, combined with expert insider tips to find the best airline ticket deals.