Commercial airlines do not typically have a doctor on call specifically for passenger medical emergencies. However, flight crews are trained in first aid and have access to medical kits on board that contain basic medical supplies and equipment.

In the event of a medical emergency on board, flight attendants are trained to assess the situation, provide initial medical assistance, and communicate with any healthcare professionals among the passengers if available. Flight crews also have the ability to communicate with medical professionals on the ground, such as a designated medical support service or a physician through radio or satellite communications.

If necessary, flight crews may request assistance from any healthcare professionals on board who volunteer their help. However, it is important to note that these individuals are not obligated to provide medical assistance and can choose to do so based on their own judgment and capabilities.

In some cases, if the medical situation is severe and requires immediate attention, the flight crew may decide to divert the aircraft to the nearest suitable airport to seek medical assistance on the ground.

Passengers who have known medical conditions or concerns are encouraged to consult with their healthcare providers before traveling to ensure they are fit for air travel and to address any specific concerns they may have.