If you can use credit cards responsibly, look into credit card churning for points. I fly business class for any extended flight and I pay less than what economy would cost.
Absolutely this, people paying cash and with debit cards end up just subsidizing points redemptions. Merchants aren't eating card fees (typically 1.5-3% of a purchase), they just baked it into prices.
With a stable income, watching what you spend, and auto-pay, carrying a card balance is super easy to avoid these days.