I was asking about using a manual scooter on Yom Tov only (not Shabbat) as we are allowed to carry on Yom Tov. Children are allowed to use scooters on Yom Tov. I have a nurse for my mom for the morning and would like to get home sooner in the afternoon when the nurse is not working.

ב"ה Shalom I have in the meantime I've edited my previous answer, so that it addresses Yom Tov and Shabbat. Indeed, we carry on Yom tov, but carrying the scooter is not the issue. All major Halachic authorities probably for the last 100 years have forbidden the use of bicycles or scooters (long before there were electric ones) on Shabbat or Yom Tov. Therefore , however noble your desire to get back to your mother earlier, it does not change the existing custom of not using a bicycle or scooter on shabbat or Yom Tov. (קצות השולחן קי בדה"ש טז; ישכיל עבדי ג, יט; ציץ אליעזר ז, ל; שאלת יעקב מה, כה"ח תד, ח; שמירת שבת כהלכתה ט"ז : יח.) Undeniably, children under the age of Bar Mitzva are allowed to engage in certain forms of games and fun but this does not always apply for adults.( שמירת שבת כהלכתה ט"ז : יח.) All the best