Airline baggage regulations, what about hairspray and spare batteries?

When traveling abroad or taking a domestic flight, one of the things we worry about the most is baggage regulations. In particular, it is often confusing whether hairspray, which is essential for maintaining a hairstyle, or a portable charger, which is essential for long-distance travel, can be brought on board or should be checked in. Today, I will briefly summarize airline baggage regulations that many people in their 20s and 30s are curious about.

✈️ Hairspray, can I bring it on board?

Hairspray is mostly classified as a liquid, so there are restrictions on the amount you can bring on board.

Allowed amount on board: Only 100ml or less 
(100ml or less per container, up to 1L total)

Allowed amount in checked baggage: Varies by airline, but generally only individual containers of 500ml or less are allowed, up to 2L (4 pieces) total

Note: Aerosol products may contain flammable ingredients, so some airlines may prohibit certain products.

💡 Real-life experience
"Once I tried to bring a 200ml bottle of hairspray on board, but it was caught at the security checkpoint. I ended up having to throw it away... Since then, I've been carrying a 100ml bottle for travel!"

🔋 Can I check-in my spare battery or bring it on board?

Since spare batteries are lithium-ion batteries, they can only be carried on board.

Carry-on capacity: Unlimited for 100Wh or less (generally 27,000mAh or less), 100~160Wh requires airline approval
Checked baggage allowed: ❌ prohibited (lithium batteries are fire hazards and cannot be checked)
Note: There is a risk of fire if the battery is damaged or impacted → Always store in a case or pouch

💡 Real experience
"Once I checked in with a portable battery in my checked baggage, but my name was suddenly called and I had to go to the desk. I found out that portable batteries must be carried on board. Since then, I always carry it in my carry-on bag."