If there is a lesion or more in my lung and its too dangerous for a biopsy because of air pockets surrounding it how will they know if its cancerous ?

Need biopsy: In order to "prove" cancer a biopsy is needed. There are only a few cancers (eg, hcc, germ cell) that don't need biopsy. Can't comment on the individual situation and options, but a lung cancer diagnosis needs a biopsy.

Biopsy: The specifics of location and anatomy will have an impact. Additionally degree of disease in your lung will impact risk of biopsy. That said, if too risky for radiology guided biopsy, you may be a candidate for inreach/em-navigation bronchoscopy with biopsy. Again, risks greatly depend on your overall health, location of lesion, and conditions of lung/pulmonary status.