Sure, you tip your restaurant server and your hairdresser and cab drivers. You might even offer your postal carrier a holiday bonus. But did you know that flight attendants frequently get tipped, too?

That's the finding of a question asked at Airfarewatchdog.com, where about 27% of roughly 900 respondents said they had, "as a thank you for doing a good job" or "for going out of the way to make me more comfortable." Nearly three quarters, 73%, said they don't tip flight attendants.

The practice is controversial, though.

For one thing, some point out that one typically tips after a service has been performed, in recognition of a job well done. When money is given to a flight attendant, it's often done at the beginning of a flight in the hope of ensuring good service. Thus, some call it a "bribe."

In 2006, an article  in Budget Travel magazine featured "confessions" of a flight attendant, noting that tips or gifts are "greatly appreciated." Some responses to the article came from other attendants, one of whom noted: "I am a flight attendant who has worked for [a] major carrier for 23 years. I have never and will never accept a tip from a passenger no matter how much he 'insists'. The 'free round', that your flight attendant confessed to, is not hers to give." She added, "one person in uniform does not speak for all of us."

In addressing the topic, travel writer  Caroline Costello has noted, "There isn't much of an economic foundation" for tipping flight attendances, as they "aren't dependent upon tip income in order to achieve a livable wage." (Per 2010 data  from the Bureau of Labor Statistics, the median salary is $37,740.)

TravelSort.com points out  that tips can be insulting to the many attendants who consider themselves professionals (after all, their job involves a lot of public safety responsibility, not just serving drinks), and that it isn't even likely to foster good repeat service, as few of us are regularly served by the same staff. Many airlines don't permit their employees to accept tips, anyway.

If you encounter exceptional service in an airplane, consider getting the attendant's name and sending a letter to management. A commendation that sits in an attendant's file for years can be more powerful in the long run than a few dollars pressed into a hand that many not even welcome them.