Only way is with an airline approved power bank that has an outlet. If you're in the US, you'll want to look for power banks that have a 3-prong outlet and don't exceed the FAA / TSA limit of 100Wh/27,000mAh. Individual airlines may have their own further restrictions. I have the same issue with my 2020 Razer Blade 15. The 230w power supply exceeds the 75w airplane outlets. And Razer didn't introduce USB-C charging until their late 2020 models. I see that the latest Razer Blade 18 in 2024 accepts 25-100w USB-C chargers. EDIT: ^^^ I don't think a 100Wh/27,000mAh is enough to charge the laptop, it won't provide enough watts. Having not tried one myself yet, I'm not sure what the results will be plugging into it.