Yes, you can carry an electric trimmer on a flight, but the rules for where to pack it depend on its battery type. If the trimmer is battery-operated (specifically with a built-in lithium battery), most international aviation guidelines—and security at major hubs like Delhi or London—recommend or require carrying it in your hand luggage (cabin bag). This is because lithium batteries pose a "thermal runaway" risk in the cargo hold where they cannot be easily extinguished. If the trimmer is a simple corded model or uses standard AA batteries that are removed, it can safely go in your checked baggage. The blades on standard beard trimmers are generally considered safe and are not categorized as "prohibited sharp objects" like straight razors or large scissors. To ensure a smooth security check, it is wise to keep it in an accessible pouch in case an agent needs to inspect the battery or verify the device.