Goldman Sachs analyst Catherine O'Brien upgraded United Continental Holdings (UAL) to Buy from Neutral with an unchanged price target of $108. The analyst sees a better risk/reward for the shares relative to Spirit Airlines (SAVE), a stock she downgraded this morning to Neutral from Buy. There is downside risk to the consensus earnings forecasts for Spirit while United's estimates have appropriately incorporated tougher second half 2019 comparables, O'Brien tells investors in a research note. She also believes that "several recent risk factors" to United's outlook have been priced in at current levels. Further, United is likely over the next 12 to 36 months to sign a new contract with improved economics with its co-brand credit card partner Chase, contends O'Brien.