thomsonfly.com contains a hidden booking form. They don't seem to like bookings.
The reason? The booking form is within a table that is styled to be hidden:
<table class="fullwidth" id="hometable" style="clear: both; visibility:hidden;">
Another part of the code is hidden from non-IE browsers with conditional comments:
..and there is some scripting that will remove the "loading" screen and show the search form if UA is IE. Naturally since the "loading" message is hidden with conditional comments, this:
(document.getElementById("loadMessage")).style.display = "none";
"Thomsonfly – the low fares airline that goes further to confuse you."