In 1915, at the airfield in France of 59 Squadron Royal Flying Corps, Major Brand, [Neil Hamilton], the squadron leader, and his adjutant Phipps, [Edmund Breon], anxiously await the dawn patrol. Brand has lost 16 pilots in the previous two weeks, nearly all green replacements with little training and no combat experience, and he is ordered to send up tomorrow what amounts to a suicide mission. Captain Courtney, [Richard Barthelmess], leader of A Flight, and his good friend “Scotty” Scott, [Douglas Fairbanks Jr.], return, but two of the replacements are not so lucky and another, Hollister, [Gardner James], is severely depressed by the death of his best friend. The survivors repair to the bar in their mess for drinks and fatalistic revelry. Courtney does his best to console Hollister, but the youngster breaks down in grief.
When Brand announces the next day’s dawn patrol, Courtney tells Brand he does not have enough men. Brand retorts that more replacements are on the way. From the four green pilots, Courtney picks the two with the most flying hours to go on the mission. Only four return this time; Scott has been lost along with the two new men. Courtney tells Brand that Scott went down saving Hollister. Just then, British troops bring in the German who downed Scott, Hauptmann von Mueller. Courtney overcomes his initial rage when Brand informs von Mueller that it was Courtney who shot him down and the German graciously acknowledges him. Courtney then offers the German a drink. The guilt-ridden Hollister tries to attack the prisoner, but is restrained. Then, a grimy Scotty appears.
B Flight is mauled next. Just after its wounded leader, Captain Squires, informs the squadron that the dreaded von Richter is now their foe, an enemy aircraft flies low over their aerodrome and drops a pair of trench boots. Attached is a taunting note telling the British pilots that they will be safer on the ground. Brand warns his men that the boots are intended to incite inexperienced pilots into trying to retaliate. He forbids any takeoffs without orders. Courtney and Scott disregard the prohibition, taking off in the dawn mist after stealing the boots from Brand’s room. They fly to von Richter’s airfield, where the black-painted fighters are being readied for the day. Courtney and Scott bomb and strafe the field, destroying most of the German aircraft and shoot down two which try to take to the air. Courtney then drops the boots. Von Richter retrieves them and shakes his fist at the departing British. Courtney is shot down recrossing the lines, then rescued by Scott, whose aircraft is also hit by anti-aircraft fire. When leaking oil blinds Scott, Courtney talks him down to a crash landing behind their own trenches.
Brand’s outrage at their disobedience dissipates when headquarters congratulates him for the success of the attack and promotes him “up to Wing.” Brand takes cruel pleasure in naming Courtney to take command of 59 Squadron. Soon, Courtney is forced to acquire all the qualities he hated in Brand. When Scott’s younger brother Donnie is posted as a replacement, [William Janney], Scott begs Courtney to give him a few days so that he can teach his brother the ropes. Courtney tells him there can be no exceptions. Unbeknownst to Scott, Courtney calls headquarters to plead for a few days of training for his replacements but is turned down. Von Richter shoots down Donnie in flames the next morning, for which Scott blames Courtney.
Brand gives Courtney orders for a very important mission. An aircraft must fly low and bomb a huge munitions dump 37 miles (60 km) behind the lines. Brand bans Courtney from flying the mission, so Scott disdainfully volunteers. They reconcile and Courtney gets his friend too drunk to fly, then blows up the dump himself. Afterwards, von Richter intercepts Courtney, who outflies and shoots down two of the Germans, including von Richter, but is killed by a third pilot. Command of the squadron devolves to Scott. He lines up the depleted squadron for orders just as five replacements arrive. He stoically tells A Flight to be ready for the dawn patrol.
