Guess the vehicle riddles!

I have six wheels and sometimes more. People fill me with dirt, sand, or rocks. I carry loads wherever you want. What am I?

I am a vehicle with four tires. You have to wear a seat-belt when you use me. I am the most seen vehicle on the road. What am I?

I have wheels and many seats. I can take dozens of students. We go to school and home again. What am I?

I am long. My wheels roll only on rails. I move from station to station. What am I?

I have two wheels. I have pedals for you to cycle. Somestimes I have a bell. You can ride on me. What am I?

I have no wheels or wings. The wind makes me move. You could sail me on a little pond. What am I?

I take passangers from country to country. I can fly from hours to hours. I land at airports. What am I?