Low-cost carrier Ryanair are expanding rapidly and have been tipped to become Europe’s biggest airline, following the order of 100 new aircraft in a deal with Boeing worth around 5 billion Euro (Canniffe, 2002). Ryanair boast that 92 per cent of bookings are now being conducted online (www.mii.ie 2001) and that their profits are up by 35 per cent in the last three months of 2001 (www.ryanair.com 2002). In comparison Aer Lingus, a more traditional full service airline has 20 per cent of the company's customers booking via the web (Carey, 2002). They are currently carrying out a survival plan, and have been described as ‘haemorrhaging cash’ (www.washingtonpost.com, 2002) and are facing losses of up to £170 million in 2002 (McManus, 2001). At the Dublin Institute of Technology, we are conducting research into the online services of the two major Irish players Ryanair and Aer Lingus, drawing on the various methodologies and web usability guidelines in the literature. From this we may establish whether the usability of both sites reflect their business success or failure.