1.Soon I was back on my feet again and following him to collect a hovering carriage driven by computer.
主系表结构：主语I,was系词,后边的是表语.
2.These carriage float above the ground and by bending or pressing down in your seat,you can more swiftly.
并列句：and连的两个简单句
These carriage float above the ground是主谓结构：These carriage 是主语,float是谓语.
by bending or pressing down in your seat,you can more swiftly.是主谓结构,原句好像少了个谓语动词.