Check out the companies making the biggest moves in premarket trading:

Delta Air Lines — Shares popped 2% in the premarket after the airline projected “record advance bookings for the summer.” It expects sales in the current quarter to increase by 15% to 17% over last year, topping Refinitiv estimates of 14.7%. Delta forecasted adjusted earnings per share of between $2 and $2.25, versus the $1.66 expected by analysts.

United Airlines, American Airlines — Shares of other airlines also rose after Delta signaled strong demand for travel. United Airlines gained more than 2% and American Airlines rose 1.9%.

First Solar —The solar stock slid 1.4% following a downgrade to hold from buy by Deutsche Bank. The firm said the stock is expensive after its recent rally.

Merck — The pharma giant gained 1% in the premarket after being upgraded by Citi to buy from neutral, saying its drug pipeline is underappreciated. The Wall Street firm boosted the stock’s price target to $130, which implies 14% upside from Wednesday’s closing price.

Steven Madden — Shares rose about 2.7% after being upgraded to buy from neutral by Citi. The Wall Street firm said it expects Steve Madden to begin seeing stronger wholesale reorders in the second quarter.

Novo Nordisk — The maker of diabetes and weight loss drugs Ozempic or Wegovy moved about 2% higher in the premarket after being upgraded by Credit Suisse to outperform from neutral. The Wall Street firm said growth in the drugs has “significantly outperformed” its expectations.

— CNBC’s Alex Harring contributed reporting.