Worldcon air tix: might want to buy now.
Tickets were $900 and up r/t from the northeast US a few weeks ago; the Interaction blog reports $620 from NYC, and I bagged BWI-MAN/GLA-BWI (I hear there are good scones in Harrogate) on US for $665 yesterday. For those who got a fat tax refund, CO has $1800 r/t business class from their website.
