Flapping or glottalization?

One of my students raised a question about an articulation of English phrase.

1. Flapping

When you pronouncing "it was" in casual, connected speech, could it be sounded like "idwas" or "irwas"? Like "water" as "warer", or "fatty" as "fady".

2. Glottalization

In the same situation, can glottalization occur and pronounce as "it<glottal stop>was"? Like "button" as "bu<glottal stop>un" or "mountain" as "moun<glotal stop>un".

Thank you.

Hi,

"writer" doesn't sound like "wider", it sounds like "rider".
Anyway, T's are sometimes tapped. It usually happens when T's are between two vowels and the following vowel is not stressed at all (not even a secondary stress on it). Example: Betty bought a bit of...
It often happens in other cases too, for example when the following sound is not really a pure vowel sound, but you could say it's "almost" a vowel. Examples are L's and R's. Examples: better, heater, bottle, little.

W-sounds and Y-sounds don't lead to tapped T's.
It was ---> I(t) was - the T is not released/glottal stop
about you ---> abow chyoo - T and Y form a kind of CH sound.

American English comes mostly from British English but long before Received Pronunciation. In British English, we often hear 'bottle' as 'bo - ul' with no indication that any 't' existed in the word. This is a common feature of London accents, especially cockney.