Key TakeawaysCarvana's quarterly profit soundly beat analysts estimates and it boosted its outlook for the full year, fueled by increased demand for used cars.Carvana's stock price soared more than 20% Thursday after the positive earnings news.The online used-vehicle retailer set records for adjusted EBITDA, adjusted EBITDA margin, and GAAP operating income.Carvana sees full-year adjusted EBITDA "significantly above" the high end of its previous estimate. Rising demand for used cars helped online used-vehic ...