The Flames assigned Plett to their minor league affiliate, the Tulsa Oilers of the Central Hockey League (CHL), for the 1975–76 season where developed under the team's coach, and former NHL enforcer, Orland Kurtenbach.
Willi Baumeister | Willi Forst | Willi Sänger | Willi Plett | Willi Lippens | Willi Williams | Willi van Ooyen | Willi Hennig | Willi Braun | Chilli Willi and the Red Hot Peppers | 40. Fallschirmjägerbataillon Willi Sänger | Willi Weber | Willi Veller | Willi Stöhr | Willi Reschke | Willi Oberbeck | Willi Ninja | Willi Kronhardt | Willi Hennig Society | Willi Gerdau | Willi Frommelt | Willi Fels | Willi Arlt |
Fans loved Howatt for his scrappy, energetic style of play and, most of all, his willingness to stand up to the giant enforcers of his generation such as Dave Schultz, Paul Holmgren, Barry Beck, Dave Semenko, Behn Wilson, Bob Kelly, Danny Gare, Willi Plett, Terry O'Reilly, Stan Jonathan, Wayne Cashman, Bryan Maxwell, Jay Wells, Tiger Williams, Dave Hoyda, Jim Korn, and many more.