What is Process Costing ? why is it important? How to use it in the Airline simulation?

please provide an example. I have attached an income statement if it helps

Thanks

Income Statement Item Value % of Gross Revenue 100.0% 9.1% 9.7% 81.2% 62.8% Gross Revenue Commissions Refunds Net Revenue Direct Flight Expense Marketing Expense Lease Payment Depreciation General & Administrative Total Operating Expense Interest Expense Profit Before Tax Less Income Tax (40%) Net Profit $2,688,518 $244,625 $260,786 $2,183,107 $1,689,234 $36,000 $132,000 $96,000 $166,200 $2,119,434 $54,919 $8,754 $3,501 $5,253 1.3% 4.9% 3.6% 6.2% 78.8% 2.0% 0.3% 0.1% 0.2% Income Statement Item Value % of Gross Revenue 100.0% 9.1% 9.7% 81.2% 62.8% Gross Revenue Commissions Refunds Net Revenue Direct Flight Expense Marketing Expense Lease Payment Depreciation General & Administrative Total Operating Expense Interest Expense Profit Before Tax Less Income Tax (40%) Net Profit $2,688,518 $244,625 $260,786 $2,183,107 $1,689,234 $36,000 $132,000 $96,000 $166,200 $2,119,434 $54,919 $8,754 $3,501 $5,253 1.3% 4.9% 3.6% 6.2% 78.8% 2.0% 0.3% 0.1% 0.2%