U.S. stock indexes were mostly higher in midday trading Thursday as Wall Street sized up quarterly results from several companies including Delta Air Lines, which led a rally in airline stocks after releasing a solid outlook for the rest of this year.

Wall Street indexes hit record highs as investors remain optimistic despite tariff announcements. Delta Air Lines provided an encouraging profit forecast, boosting airline stocks. The market was invigorated by Nvidia's valuation milestone and lower jobless claims.