Ivan Feinseth says the demand for cruises is "on fire" and maps out his reasons for continuing to be bullish on the travel space. He says the cruise companies continuing to churn out new ships and new experiences. Ivan sees the biggest upside in Norwegian Cruise Line (NCLH) and says for cruise companies the biggest earnings indicator is "on-board spending." Ivan previews Carnival (CCL) earnings and holds a $38 price rating on its stock. Ivan does note that geopolitical tensions could be an issue to monitor as a potential headwind.