Air transportation of patients to specialised health care services has become ever more important in modern health care. Air transport has the advantage of a swift transport and the possibility to cover large geographical areas. Air transport may be used for the pre and postoperative transport of patients with brain tumours. Preoperative transport of patients harbouring brain tumours seem to be safe in most cases even if there are a few reports reporting clinical deterioration during and after air transport. Results from microdialysis of normal brain tissue and tumour tissue have shown only minor metabolic changes during and after air transport. In case of postoperative air transport of patients operated for brain tumours the presence of intracranial air be associated with an increased risk. Intracranial air can be treated as an ideal gas and will expand as the cabin pressure in the aeroplane decreases. Air trapped in the intracranial cavity cannot easily expand, however, and this may result in an increased intracranial pressure. Therefore it may be recommended that patients with a large amount of intracranial air should be transported with ground transportation or with air transportation where the cabin is pressurized to sea level.