] How common was it for people to ride horses during the Regency period? Were they only for the gentry and aristocracy? I ask because in several JA novels characters are mentioned as being able to ride, but characters whom I thought should be riders are not mentioned on a horse (does Emma ever ride a horse, have I missed it?). Also, was it more common for men to ride and women to use carriages?

Ahh, a subject dear to my heart. :-> The horse has played a varied and indispensable role in English history.
The horse had several functions. And, several kinds of horses were used to fulfill these functions. To begin with, the horse was for the rich. The poor man could not afford a horse for pleasure riding or for farming, having instead to use a cheap donkey. A gentleman would have hack horses, for riding around from place to place, a hunter, specifically used for the fox hunting (bred specifically for this job and used exclusively for it--you would ride a hack to the meet to spare the horse for its job of hunting), and, if he wished, racehorses (Thoroughbreds, bred by Charles II for that purpose). If I understand the sport right (particularly steeplechasing), the gentleman could choose whether to ride the race himself or employ a jockey to do it. Actually, I know this to be the case; I'm just not positive it was this way in the Regency--I believe it to be, however. Fat men would ride cobs, short fat horses who could bear their weight, and women would ride gentle horses or ponies--sidesaddle, of course. The heavy horse was used for farming, and by the nineteenth century, many breeds of farm horse existed; a few British examples include the Shire, the Suffolk Punch, and the Clydesdale (of Budweiser fame). I may be wrong here, but my research has so far indicated that women rode for exercise and men for pleasure and transit. I hope this helps and that I haven't thoroughly bored you!