Typically, the employer is responsible for all "ordinary and necessary" expenses incurred during a business trip. In 2026, most companies operate on an reimbursement basis, where the employee pays upfront for flights, hotels, and meals and is repaid after submitting an expense report with receipts. Larger corporations often provide a corporate credit card, which direct-bills the company for major costs. Additionally, many businesses use a "Per Diem" system, providing a fixed daily allowance for food and incidentals based on the destination's cost of living. It is a high-fidelity requirement for employees to adhere to the company's travel policy, which may dictate which airlines to use or set a "price cap" on nightly hotel rates. Under US and EU labor laws, while the company covers the core costs, the employee is generally responsible for personal expenses like souvenirs or extra days added for leisure. Always ensure you have a clear, written approval for all anticipated costs before departure to avoid "High-Fidelity" financial disputes upon your return.