The nonrigid airship ​ — sometimes called a blimp — ​ has no frame but simply consists of a balloonlike bag kept in shape solely by the pressure of the gas inside.
Pehmetel õhulaevadel sõrestikku pole. Need koosnevad üksnes õhupallisarnasest kestast, mille vormi hoiab vaid selles sisalduva gaasi rõhk.