Squadron Commander Lord Flashheart is a headstrong ladies man with a massive ego, thinking himself a brave hero and God's gift to women. George and Baldrick idolize him. However, Blackadder loathes him, calling him a prat. In turn, Flashheart makes fun of Blackadder, calling him 'Slackbladder'. He is well known for making many sexual innuendos, and for his catchphrase "WOOF WOOF". He appears in the episode "Private Plane".

Flashheart is first seen when his plane crashes near Captain Blackadder's dugout. He knocks Blackadder to the ground and points a gun at him, thinking he is a German soldier. Blackadder corrects him and goes on to insult him. Flashheart laughs off the insult and hits Blackadder again. He then seduces Bobby and encourages George and Baldrick to join the Royal Flying Core. Blackadder decides to join as well, after noticing all the perks pilots get.

Flashheart acts as the instructor during Blackadder, George and Baldrick's flight training, which consists of Flashheart telling the men to "Always treat your kite like you treat your woman; get inside her five times a day and take her to Heaven and back." He also reveals that the squadron is named the 'Twenty Minuters' because the average life expectancy of new pilots is only twenty minutes.

Flashheart later appears with George to save Blackadder and Baldrick from the enemy trench at George's request, after Blackadder crash landed his plane in German territory. He was apparently unaware that it was Blackadder who was captured, but decides to save him, since he is there anyway. He is confronted by Baron Von Richtofen (The Red Baron) who sees him as a worthy opponent. However, Flashheart merely shoots him, and states "What a poof!" before making his escape with the others.

He appears at the end of the episode where he confronts Captain Darling on behalf of Blackadder, after Blackadder reveals he is still alive. After calling out Darling on not putting any effort into save Blackadder and Baldrick, Darling says that saving them wouldn't have been a reasonable use of their time and resources. Flashheart replies that "This isn't a reasonable use of MY time and resources, but I'm going to do it anyway!" and proceeds to headbutt Darling, knocking him out. He then makes one last innuendo and leaves with Bobby, after which Blackadder calls him a git.