Lounge access: business class ticket or Star Alliance Gold

Two things open a lounge door, and only one of them survives the itinerary that saves the most money.

The cabin on your ticket. A business or first ticket includes lounge access for that journey, from the airline operating it or its partner.

Your status. Each alliance gives the tiers of its member airlines a shared name, and that is what Star Alliance Gold, oneworld Sapphire and SkyTeam Elite Plus are: cards that work at every airline in the alliance, not only at the one that issued them. They include lounge access whatever cabin you are in, normally with one guest.

Split the trip into a cheap hop and a separate long-haul ticket, and the ticket stops opening doors at your home airport. The card does not notice.

Star Alliance Gold, Sapphire, Elite Plus: what each card opens

oneworld ranks its cards Emerald, Sapphire and Ruby, highest first. Star Alliance puts Gold above Silver, and SkyTeam Elite Plus above Elite.

Star Alliance Silver opens no lounge, which matters because Miles & More Frequent Traveller, the programme's first tier, is Silver: its own lounge access covers Lufthansa Group flights only, so a Frequent Traveller flying Singapore Airlines waits outside. oneworld Ruby opens none either, though it does give you the business class check-in desk.

A business ticket opens the lounge only where that flight departs

Star Alliance puts it plainly: as an International Business Class customer you may use any member's business lounge at the airport where your flight departs, on presentation of a boarding pass in International Business Class, for a flight leaving that day or by 05:00 the next morning. No guests. First class adds the member airlines' own lounges and one guest.

The words that matter are your flight departs. Book economy Zurich to Frankfurt and business Frankfurt to Singapore on one ticket, and the alliance rule gives you nothing in Zurich: the boarding pass in your hand is an economy one.

Airlines are often more generous with their own passengers, and some grant access on a same-day premium connection. That is grace, not a rule you can rely on at a strange airport.

What happens on two separate tickets

The rule does not change, only the goodwill. With the hop in economy and the long-haul on a second booking, your boarding pass at home is an economy one, for a journey that ends, as far as any system can see, in the staging city.

• At your home airport, before the hop. Expect no. The refusal is the policy, not a bad mood.
• At the staging airport, before the long-haul. Normally fine. That boarding pass is a premium one.
• On status instead. Unaffected. A Gold card opens the business lounge in any cabin, for you and one guest on the same flight, and it never asks what the rest of your trip looks like.

That is the case for holding a mid-tier card if you fly this way often: the split creates the saving, and the status repairs what the split breaks.

The entitlement is attached to the flight you are about to board, not to the most expensive segment of your trip.

The smaller rules that catch people out

• It is for departure, on the day of travel. Arrivals lounges are a separate entitlement. A long layover is usually fine, a stopover of a day usually not.
• First class lounges are a separate door. oneworld Emerald and, in the Lufthansa world, HON Circle and first class tickets open rooms a business ticket does not.
• A paid pass is a real answer. For one trip a year, a single entry can cost less than any route to status, and it works on an economy hop where nothing else does.

If you are weighing status against simply buying the better cabin, the arithmetic is in what airline status actually costs.