There is no brand-wide answer
Current Philips US support discourages both foil and baking paper in its listed Airfryer models because covering the base interrupts airflow and unsecured material can reach the heater. COSORI’s own maintenance guidance describes qualified liner use without blocking vents or touching the heating element. These are different model and component instructions, not a universal contradiction to erase.
Before lining anything, identify the exact US model and find the liner or accessory section of its manual. Do not transfer permission from an oven tray to a drawer pan, or from one COSORI product to every product with the brand name.
The two practical questions
First, where must air move? A liner covering a perforated base or grease-collection area can defeat the intended circulation. Second, can the liner move? Philips warns that loose paper or foil without food on it may be drawn toward the heating element in its listed models. Preheating with an empty unsecured liner is therefore particularly concerning where the manual disallows it.
A sheet advertised as “air-fryer compatible” is not proof of safe compatibility with your exact model. Its dimensions tell you only whether it might physically fit. Our accessory finder marks official exact-model matches separately from an estimated geometric fit.
When the instructions are silent
If your exact model’s manual does not say whether a foil or parchment placement is permitted, treat it as unknown and ask the manufacturer or use the unlined cooking arrangement. Do not infer permission from a generic cleaning tip, a recipe photograph or another regional manual. A liner may make washing easier, but it can also change the airflow and cooking result.
If the manufacturer permits a liner for a named tray, keep to that placement and any temperature or loading conditions it states. Still verify food doneness with a thermometer when applicable; a liner cannot certify cooking safety. Clean and inspect the appliance by its manual after the session.
Use a source-aware checklist
Write down model number, market, cooking component, liner type, allowed position and conditions from the official source. The exact model profile and manual finder establish identity; the compatibility tool helps avoid treating size alone as approval. If official documents disagree across revisions, keep the permission unresolved until the manufacturer confirms the applicable instructions.
Guide authored and sources checked 2026-09-15. No hands-on testing claimed.