Franz Xaver Freiherr von Werra (13 July 1914 – 25 October 1941) was a German World War II fighter pilot and flying ace who was shot down over Britain and captured.

He was the only Axis prisoner of war to escape from Canadian custody and return to Germany apart from a U-boat seaman, Walter Kurt Reich, said to have jumped from a Polish troopship into the St. Lawrence River in July 1940.

In a sortie on 25 August during the Battle of Britain, he claimed a Spitfire west of Rochester, and three Hurricanes, as well as five destroyed on the ground for a total of nine RAF planes eliminated.

The Australian ace Flight Lieutenant Paterson Hughes (234 Squadron) was posthumously given half of the credit, in The London Gazette 22 October 1940 citation awarding him a bar to his DFC.

He was digging with a pick axe while guarded by Military Police Private Denis Rickwood, who was armed only with a small truncheon.

At a regular stop, while a fruit cart provided a lucky diversion and other German prisoners covered for him, Werra slipped over a dry-stone wall into a field.

On the evening of 10 October at around 11:00 p.m., two Home Guards found him sheltering from the rain in a hoggarth (a type of small stone hut used for storing sheep fodder that is common in the area).

He had taken along his flying suit and decided to masquerade as Captain van Lott, a Dutch Royal Netherlands Air Force pilot.

He told a friendly locomotive driver that he was a downed bomber pilot trying to reach his unit, and asked to be taken to the nearest RAF base.

At Codnor Park railway station, a local clerk became suspicious but eventually agreed to arrange his transportation to the aerodrome at RAF Hucknall, near Nottingham.

While Boniface went to check this story, von Werra excused himself and ran to the nearest hangar, trying to tell a mechanic that he was cleared for a test flight.

His group was to be taken to a camp on the north shore of Lake Superior, Ontario, so Werra began to plan his escape to the United States, which was still neutral.

After crossing the frozen St. Lawrence River, von Werra made his way to Ogdensburg, New York, arriving several months before the US entered the war and turned himself over to the police.

The immigration authorities charged him with entering the country illegally and Werra contacted the local German consul, who paid his bail.

Werra was assigned the task of improving German techniques for interrogating captured pilots, based on his experiences with the British system.

Two days later, Oberleutnant Wilfried Balfanz, the commander of I. Gruppe of Jagdgeschwader 53 (JG 53—53rd Fighter Wing), was killed in action.

According to Obermaier, von Werra was credited with 21 aerial victories, eight of which over the Western Allies and thirteen on the Eastern Front, plus five further aircraft destroyed in ground attack missions.