You can get a domain for .99 cents! 1and1.com . It's not expensive at all, if you just use a subdomain you won't get any long term pilots. It also makes you and your virtual airline look bad. Show me a virtual airline with a subdomain that is successful, you won't find any. Try to strive for perfection and don't always take the "free" route because it shows it really does, it shows that you don't want to commit and people can tell that your just 50% committed. Take the advise here seriously, these people have successful virtual airline and are growing everyday.