I’ve written in the past how good Frontier Airlines’ customer service has been to me and my family at various times. However their web site has one really annoying flaw in it: It appears to be built for Internet Explorer only. That was annoying. Also annoying was the lack of clarity for what format my phone number was supposed to take in their web form. Further, their error page basically says, “Call our toll free number since something’s not right.” Basically, they need to buy Defensive Design
and learn good user friendly design.