Airline passengers continued to be subject to delays and increased security checks on Friday (August 11, 2006) after British police foiled a suspected plot to blow up several aircraft mid-flight between Britain and the United States the day before. Departure halls in Frankfurt continued to be jammed with queues of people waiting, airlines were resuming normal services, but passengers were subject to increased security checks. Most were understanding of the measures though. "I think that the reactions are a lot stronger now because of all the sensitivity, and people tend to overreact at first, but it can't hurt - quite the opposite," passenger Bernd Moos said. But the critical alerts in both Britain and the United States caused massive disruption to air travellers and highlighted the need to invest in new airport checkpoint technology to screen passengers and hand luggage for explosives. "The more transparent it all is the better," another passenger Mechthild Lueck said. "That way nothing can happen, I think that is ok. I don't have anything to hide, and who does have something to hide, they shouldn't be getting in the plane." British and U.S. authorities have banned travellers from carrying liquids and other gel-based products onto planes, a step also taken by some Asian airlines on Friday for flights to Britain and the United States. "Liquids are not allowed in hand luggage, at least not in planes going to America or Great Britain. There are different instructions as to electronic devices, in that case it is better to check with the airline before flying," Frankfurt Airport Spokesman Klaus Busch advised passengers. An al Qaeda plot to blow up airliners with liquid explosives was uncovered as far back as 1995, but authorities have never previously judged the risk sufficient to ban the carrying of fluids onto planes. That could change, perhaps for good, with the uncovering of this week's Islamist militant plot to blow up planes with chemical bombs disguised as drinks. Current airport security typically involves a five-layered process of screening checked-in luggage, with multiple X-rays and CT scans. That is too unwieldy and time-consuming to apply to passengers and their hand luggage. Instead travellers pass through a metal detector gateway and their bags through an X-ray machine, with a random sample also checked for explosives residue using trace particle detectors.