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 and 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.

Harley-Davidson — Shares dropped nearly 4% in the premarket after UBS said retail declines for the motorcycle maker in the first quarter may be worse than expected. The Wall Street firm said retail sales could be down close to 20% at U.S. dealers.

— CNBC’s Alex Harring contributed reporting.