A US woman was forced to cancel her entire trip to Spain after an airline caught her attempting a popular money-saving travel hack. Theresa McKinney had originally booked a trip from her home city of Cleveland, Ohio, to Madrid , with a short stopover in Newark, New Jersey. However, upon realising her husband was going on a business trip to Boston , Ms McKinney decided to accompany him as she had ‘always wanted to explore the New England state’, reports Insider . When she tried to change her flight from Cleveland to Boston, McKinney was told by United Airlines that the cost would be $900. Instead, she booked a flight from Boston to Newark for $60 – again with United – intending to miss the first leg of her booking and then catch the second leg of her planned flight to the Spanish capital. This is a version of a trick known as skiplagging . Passengers will deliberately book a flight with a layover as they are often cheaper, but will skip the second leg, with the layover city actually being their planned destination. In this case, Ms McKinney’s circumstances saw her skip the first leg. However, Ms McKinney had her flight to Newark cancelled by United for being a duplicate booking, meaning she had to reach the New Jersey airport on a JetBlue flight in time to join the plane heading to Europe. In the end, her choice to go to Boston cost her the entire holiday. ‘Once I landed, an agent pulled up my itinerary and asked why I wasn’t on my flight from Cleveland,’ she said. ‘I didn’t get why I had to explain my personal travel arrangements, so I said plans had changed and I needed to fly out of Boston instead.’ Skiplagging is not illegal, but it is against most airlines’ terms and conditions. ‘They told me because I didn’t get on my first flight from Cleveland, my entire itinerary would be cancelled, and my only option was to rebook my ticket for the (apparently unavoidable) fare difference of $900’, she added. Instead of paying the fee, McKinney cancelled her plans as they were ‘mostly refundable’, and later received a $439 airline voucher for the cost of her original trip. ‘You’ll never catch me intentionally missing a connection again,’ she added. The Independent has contacted United Airlines for comment.