United Airlines flights in several parts of the United States were hit with delays Tuesday due to what the company called a problem with its computer networks. Customers also said they could not log into United\'s website, crucial for making reservations and printing out boarding passes. United acknowledged the problem, which surfaced Tuesday afternoon with customers tweeting the company about their problems. \"We have a network outage and are working to get systems back online,\" United said in a statement on its Facebook page and Twitter account. Customers in Buffalo, Des Moines, Iowa; Houston, Newark and other cities complained of flight delays and the company\'s inaccessible website, according to various media reports and Twitter messages. \"We do have an outage and we\'re working to fix it,\" United told one customer via Twitter.