I never realized just how complex the mental process of picking an airline flight has become.

As an expert on the subject, I was surprised to discover that I didn’t know all the facts, fare restrictions and customer-service limitations when I selected Delta Air Lines for two roundtrip tickets from Boston to New York’s LaGuardia airport. I was connecting to an Iberia Airlines flight to Spain out of JFK.

Not that Delta cared.

Here are the details.

1. Decided to fly in and out of LaGuardia and take a taxi to JFK. When purchasing my tickets between Boston and JFK, I noticed that BOS-JFK flights were far more expensive than BOS-LGA flights. That resulted in my decision to take a $30 taxi between JFK and La Guardia (LGA) to save about $200 on each ticket.

2. Prices were similar. When I searched Orbitz, Expedia and Travelocity, roundtrip LGA-BOS was about $180 on Delta, US Airways and American across the board.

3. When to fly. I was landing at 3:30 p.m. at JFK. I figured an hour to clear customs and an hour to get from JFK to La Guardia and at least 40 minutes or so to check in luggage. Therefore, I looked for a 7 to 7:30 p.m. flight.

4. Which airlines fit best with my frequent flier programs? Deciding which airline to fly was the next step. I looked at my frequent flier miles. US Airways was already showing enough for a free flight. Delta was at about 15,000 miles. American was at about 20,000 miles.

5. Which airline had more frequent service and larger planes? OK, now Delta or American? Delta had larger planes and more frequent service, so I selected Delta, figuring that is we managed to get through customs and to LaGuardia early, there would be a far better chance to get put on an earlier flight standby.

6. I purchased my tickets. And we eventually headed off to Spain for a wonderful vacation.

Our flight from Spain to JFK was on time, landing at 3:30 p.m. We were one of the first U.S. citizens to come through passport control. Our luggage came out first on the carousel. We took our taxi directly to LaGuardia.

To this point, the trip back home had been perfect. The service on Iberia had been perfect. The food was good, service was attentive and the movie interesting. As I noted, baggage, customs and the taxi went without a hitch.

We checked in with Delta at about 4:30 p.m. and asked if we could fly standby earlier if there was space available.

The Delta check-in agents seemed nice, but their answer stunned me, “Sorry, you can not fly standby on these tickets to Boston.”

I demurred, “A ticket agent told me the Delta policy was to allow standby on flights within three hours of the originally scheduled flight for a $25 fee?”

“Yes,” answered the agent, “But this is a shuttle flight and we have different rules.”

They explained that the shuttle required a payment of $100 per ticket for changes and that “standby” really didn’t exist on Delta any more. We would be confirmed on the next flight if we paid the fee.

I asked to speak with a supervisor who informed me that since my ticket was for the 7:30 p.m. flight, it was considered a “weekend” ticket and that I would have to pay the difference between the weekend fare and the walk-up fare for a “peak flight,” plus $100 to fly earlier to Boston. Now I was up in the range of an additional $250 per ticket to get on an earlier flight.

I asked, “Can’t you put us on the flight if there are empty seats?”

“No,” Delta answered.

“So, I get to sit here while three flights leave with empty seats because of a Delta policy?” I asked, not too calmly. “This makes no sense.”

“Yes,” the supervisor stated, “You get to sit here.”

We waited for two hours while the 5:30 p.m. flight left with availability. Then the 6:30 p.m. flight left with seats available. The 7:30 p.m. flight left almost 45 minutes late with every seat filled.

We got back to Boston at about 9:30 p.m. It was 3:30 a.m. in Spain. It had turned out to be a long day of travel. A journey made almost three hours longer courtesy of Delta’s policies or the Delta supervisor’s ignorance of those policies.

Epilogue I went online and checked the Delta website under “ticket changes” to see if I had indeed misinterpreted the Delta policies.

Here is what I found on that website page.

“Effective for tickets purchased on or after Sept. 5, 2002, for travel within the 50 U.S. and Canada beginning on Mar. 1, 2003, passengers may be confirmed on another same-day flight provided coach seats are available on the requested flight. Reservations within 3 hours of departure of the new flight are subject to a payment of a $25 (USD) service charge. The $25 service charge does not apply for Gold and Platinum SkyMiles Medallion(r) members. Reservations outside 3 hours are subject to a $100 (USD) service charge, plus any difference in fares. Review Confirmation Change Fee FAQs for more information.”

I searched that web page to see if the word “shuttle” was ever mentioned at all to indicate that there were separate policies for the shuttle. The word shuttle doesn’t appear on that page. There is no mention of a separate set of policies.

I went into the Contract of Carriage and looked for the $25 ticket change fee for normal Delta flights and the $100 change fee for shuttle flights. I couldn’t find any mention of either the cost or the word “shuttle.”

Intrigued, I decided to look for the special “Shuttle” section of the Delta Web site, Perhaps here, Delta would clearly inform passengers of the significant difference between the Shuttle rules and normal Delta flight rules. No. There is no mention of any different rules, policies or regulations on the main shuttle page or on the “Frequently Asked Questions” page.

I searched further. Since the Delta agents’ condescending attitude implied that I was unfortunately ignorant of what should be obvious rules.

So I went to the Delta Shuttle News & Information page to search for this information. Again I was foiled. Delta posts no advice about shuttle-specific policies.

I sent Delta this article together with my ticket information with these questions.

Dear Delta,

Where is your shuttle-specific contract of carriage?

Where can a passenger find the specific rules and fare restrictions?

How are your fares annotated to let passengers know that different fare restrictions apply?

What are the Delta policies for passengers who show up early for a flight and ask to be put on an earlier flight on the same day than that for which they hold a reservation? Do they pay $25? Do they pay $100? Do they pay the change fee plus the change in fare? Please let me know.

Perplexed passenger,

Charles Leocha

Still no answer.