Use a sturdy knife or cleaver to cut wings into three pieces and the turkey neck into similarly sized pieces.
Preheat oven to 450°F / 230°C. Place turkey parts, onion, celery, and carrot on a sheet tray and roast for about 20 minutes, until nicely browned.
Transfer turkey and vegetables to a large saucepan. Deglaze the sheet tray with 1 cup water, scraping up all browned bits. Add the deglazing liquid to the saucepan.
Add chicken stock, thyme, and bay leaves. Bring to a simmer and cook for 45 minutes. Strain and reserve the fortified stock.
In a clean saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute until smooth.
Gradually whisk in the strained stock. Simmer for 5-10 minutes, stirring frequently, until thick enough to coat the back of a spoon. Do not salt. Cool and refrigerate if making ahead.
When ready to serve, reheat gravy and gradually whisk in turkey drippings to taste. Simmer until reduced and desired thickness is reached. Strain through a fine mesh strainer before serving to get an extra smooth consistency.