Use weakness in airline stocks to buy on the dip as a buying opportunity.For one, most grounded airline stocks are technically oversold at support, which we can walk through in just a month. About five billion people are expected to fly this year, which could result in another record year for the sector. And three, according to the International Air Transport Association (IATA), 2014 revenue could reach $996 billion this year.In addition, the latest inflation report showed that airfares are dropping, which ...