A track on a DVD can only have one of two aspect ratios- 1.33 (4X3) or 1.78 (16X9). You’ll have to letter box your 2.37 footage within one of those formats. Personally, I’d go with the 1.78 & then set up the DVD to force letterboxing on 4X3 TVs. If you go with the 1.33, and it’s played on a widescreen TV, you could wind up with a letterbox inside of a pillar box.