Airship size

howdy folk I just wanted to ask how badly do large airships tend to lag servers? I wish to have a self sutaining airship (infinite lava source) that also produces materials like iron and the such. I tend to stay on the safeside and unsimulate my airships when Im done with them to save server tps but with a bigger airship that would be incovienent and honestly lame so I was just wanting to get some opinions on how big is to big if it isnt the only airship