Two in front, two in back.
No!
No.
85 to 215 passengers - depending on the model !
None.
The original Wright Flyer held no passengers, only the pilot.
None, they are for driver only.
Yes
There is no Illinois Law at this time which specifically prohibits passengers from riding in the cargo bed of a pickup. However, the seat belt laws do restrict who can ride in the bed. The Child Passenger Safety act requires that children under the age of 16 be fastened in a seat belt or child safety seat, so no one under 16 can ride in the pickup bed. In addition, if the driver of the pickup is under 18, all passengers under age 19 must be in approved seat belts, so unless the truck has factory mounted seats in the bed, no persons under 19 can ride there.Read more: Can_you_ride_in_back_of_truck_in_Illinois
Passengers fly on a plane.
A 747-400 with 3 classes of service holds about 416 passengers. With 2 classes of service it can hold 524 passengers.
Check with the laws and requirements for your state. For Texas, it is illegal for a person or persons to ride in the bed of a truck if they are under 16. It is also illegal for children in a car seat or booster seat to ride in the front of any vehicle.
Passengers ride trains.