Plugging your laptop into your car's built-in USB port to charge is generally not recommended. These ports are typically designed for lower-power devices like phones, often delivering only 5W to 7.5W, which is insufficient for most laptops. Modern laptops, such as the M5 MacBook Air or 14-inch MacBook Pro, require significantly more power, often 70W or higher, for effective charging.

While some newer vehicles, particularly EVs, may feature more powerful USB-C ports with Power Delivery (PD) capabilities, it's not a universal standard. Always check for labels indicating PD or high-wattage charging near the port or consult your owner's manual. Assuming a standard USB port can handle your laptop's needs can lead to very slow charging or no charge at all.

For reliable laptop charging in your car, the best solution is typically a 12V USB-C PD charger. These plug into the accessory outlet (cigarette lighter) and provide the necessary wattage. Alternatively, a power inverter can convert your car's 12V outlet into a standard AC outlet, allowing you to use your laptop's original wall charger. Ensure your car's accessory port can handle the load, especially with higher wattage chargers or inverters. A portable power bank specifically designed for laptops is another viable option, but always verify its wattage output against your laptop's requirements.