The following are suggestions as to how to get a reasonable airline response if you experience a problem while flying:
Write down times and names of airline personnel (they should be wearing name tags) that you speak to. Take photos when appropriate, such as of a broken tray table.
Speak up at the time you first encounter a problem and if not satisfied with what you are told, ask to speak to a supervisor.
If you need to write a complaint, make certain you are writing a good one. The airline will need to know what flight number you took, the day and time, as well as the details of the problem. Limit your complaint to a couple of paragraphs. Conclude your complaint with what you would like from the airline, such as a refund or a new ticket.
The tone of you complaint should be calm and cordial. Saying that you will never fly this airline again is unlikely to motivate the airline to positively respond to your complaint.
Include documentation, if available, such as photos or copies of any documents.
Be reasonable regarding what you are requesting in terms of compensation.
Send your complaint via email through the airline's web site.
State that if you do not hear from the airline in the amount of time listed in its customer commitment pledge (which can be found on airlines websites and spells out how quickly it will respond to complaints) you will complain direct to the Department of Transportation and the Better Business Bureau.