United Airlines’ UAL Boeing 777 jets, one of which was involved in the emergency landing at Denver International Airport in February, remain grounded as the Federal Aviation Administration (“FAA”) continues to review the Boeing 777-200 planes with Pratt & Whitney engines, a Reuters report stated. The 777 jet involved in United Airlines’ Denver, CO incident was powered by a Pratt & Whitney engine. The aircraft had to make an emergency landing at the Denver International Airport after one of its right engines failed soon after take-off. The plane was headed to Honolulu, HI. Following this flight scare, United Airlines has pulled out 24 such jets in its fleet after the FAA said that the jets required inspections.Per the Reuters report, a Boeing spokesman said that the company was working closely with the FAA, its customers and Pratt & Whitney to “safely return PW4000-112-powered 777 airplanes to service.” Boeing has identified design changes and is working to finalize them, including a certification effort, the spokesman added.United Airlines Holdings Inc Price United Airlines Holdings Inc price | United Airlines Holdings Inc QuoteA United Airlines’ spokesman has reportedly said that the company expects "these aircraft to return to service but providing anything beyond that in terms of timelines would be premature." In July, the airline’s chief commercial officer, Andrew Nocella, had said that the grounded jets were large in capacity and were used in domestic markets on the Hawaii route and hub-to-hub. So, the company is flying “well below” the level it wants to in Hawaii, Nocella added.According to the Reuters report, The Wall Street Journal has reported that United Airlines’ 777 jets may not fly until early 2022.Zacks Rank & Key PicksUnited Airlines carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the airline space are Controladora Vuela Compania de Aviacion, S.A.B. de C.V. VLRS, SkyWest, Inc. SKYW and Corporacion America Airports S.A. CAAP. While Controladora Vuela and SkyWest sport a Zacks Rank #1 (Strong Buy), Corporacion America Airports carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.While shares of Controladora Vuela and Corporacion America Airports have rallied more than 100% in a year’s time, SkyWest shares have gained more than 37% over the same time frame. Bitcoin, Like the Internet Itself, Could Change Everything Blockchain and cryptocurrency has sparked one of the most exciting discussion topics of a generation. Some call it the “Internet of Money” and predict it could change the way money works forever. If true, it could do to banks what Netflix did to Blockbuster and Amazon did to Sears. Experts agree we’re still in the early stages of this technology, and as it grows, it will create several investing opportunities. Zacks’ has just revealed 3 companies that can help investors capitalize on the explosive profit potential of Bitcoin and the other cryptocurrencies with significantly less volatility than buying them directly. See 3 crypto-related stocks now >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report United Airlines Holdings Inc (UAL): Free Stock Analysis Report SkyWest, Inc. (SKYW): Free Stock Analysis Report Controladora Vuela Compania de Aviacion, S.A.B. de C.V. (VLRS): Free Stock Analysis Report Corporacion America Airports S.A. (CAAP): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research