no
Jeans are elastic since you can substitute jeans with track pants or other pants.
Yes there are mens pants with elastic waistbands. JcPenny, Kmart, and Target are a few places that sell them. The ones at JcPenny are called : Men's Towncraft Plain Front Full Elastic Pants
there pants that were in in like the hippie times and they have a wide flare at the bottom
Flare jeans are back in style. There are different variations of "flare" to consider. The most popular flare pants are called boot cut and they have a small flare at the bottom.
There are all kinds of threads used to sew elastic bands into pants. One can use many different threads to sew elastic into pants like wool, cotton, or simple fabric.
Out of where? Waist? Hem? Ankles?
Maternity pants with elastic closures are very comfortable and it easily fits over a woman's growing belly.
Elastic pant cuffs can be made by sewing an elastic band inside the hem of the pants. Use a seam ripper to loosen the threads of the hem, then insert an elastic band and resew the hem.
You can try stores such as Wal-Mart or Target which normally have elastic pants. If she likes dressy clothes, you might try Belk's or JCPenny. These stores carry a more sophisticated line of clothing.
North east of england
It would be easier to answer, to know what type of stretch pants one has in mind. Yoga pants, running pants and regular women's elastic waist pants could be considered stretch pants. Yoga and workout pants are available in all levels of quality and price points, at places like Big 5 sporting goods, REI, Sport Chalet, even KMart or Target. The elastic waist type of stretch pants would be available at a store like Walmart.
Elastic was first used in clothing in the 1820s, in items such as stockings and gloves. Elasticized waistbands in items such as pants and skirts came about in the mid-19th Century with the invention and patent of a machine to create elastic from waste rubber and have been widely used in every decade since the 1920s.